troubleshooting

Which command can be used to test the entire name resolution order as defined in nsswitch.conf?

Which TWO commands can be used to display the current IP address and netmask of network interfaces on a Linux system?

A Linux client is configured to use PAM for authentication against an LDAP server. The /etc/pam.d/system-auth includes 'auth required pam_ldap.so'. Users can authenticate successfully. However, when a user runs 'id username', it shows 'uid=1000(username) gid=100(users) groups=100(users)' but the LDAP group membership is not shown. Which configuration file is most likely misconfigured?

An administrator needs to mount an NFSv4 export from server:/exports/data onto /mnt/data on a client. The requirement is to use Kerberos security, a hard mount, and ensure that the NFS server does not squash root's privileges. Which line in /etc/fstab correctly implements these requirements?

An administrator needs to configure a wireless interface wlan0 with WPA2-PSK authentication and a static IP address 192.168.2.50/24. Which tool should be used to configure the wireless settings?

An administrator wants to ensure a kernel module is loaded automatically at boot for a hardware device. Which file should be modified to add the module name?

Which user can execute any command as any user without any password restriction?

A company runs a Postfix mail server that relays mail for internal clients. Users report that emails to a specific external domain 'example.org' are delayed by several hours. The administrator checks the mail logs and sees entries like: 'status=deferred (connect to mx.example.org[203.0.113.10]:25: Connection timed out)'. What is the most likely cause?

A Samba share is configured with 'guest ok = yes'. What must also be configured to allow guest access?

Which THREE actions are typically required to configure a VLAN interface on a Linux system?

A client on the 192.168.2.0/24 network cannot obtain an IP address. Other clients on that subnet work fine. The DHCP server logs show no request from the client's MAC. What is the most likely cause?

An administrator wants to allow SSH access from the internal network (192.168.1.0/24) only, using nftables. Which rule should be added to the filter table input chain?

A small company runs a LAMP stack web server with Postfix mail server on a single Ubuntu 22.04 instance. The web server hosts a PHP application that sends password reset emails via the local mail server using PHP's mail() function. Recently, users report that password reset emails are not arriving. The administrator checks the mail log and finds that messages are being accepted by Postfix but are not being delivered. The mail queue shows messages with the status 'deferred'. There are no obvious errors in the mail log. The server has sufficient disk space and memory. The administrator suspects a DNS resolution issue. Which of the following is the most likely cause of the deferred mail?

The server is unable to communicate with hosts on the 192.168.2.0/24 network. Based on the exhibit, what is the most likely cause?

A system administrator is setting up mutual TLS (mTLS) for communication between a web server and a backend application on a Linux server. The security team requires encryption and proper certificate management with automated renewal using open-source tools on a small budget. Which solution should the administrator implement?

An administrator has configured Samba as a domain member for an Active Directory environment. For user authentication via winbind, which daemon must be running?

An administrator needs to add a static route to the destination network 192.168.100.0/24 via gateway 10.0.0.1. Which TWO of the following commands accomplish this? (Choose two.)

An administrator needs to configure an NFS client to mount an export from an NFSv4 server that requires Kerberos authentication. The client should mount the export at boot time. Which of the following must be ensured for the mount to succeed automatically?

A system administrator wants to enforce key-based SSH authentication for all users on a server, disabling password authentication. Which two commands must be executed to achieve this? (Choose TWO.)

Which TWO commands can be used to rebuild the initramfs on modern Linux systems? (Choose two.)

An administrator sets up a Samba server with 'security = user'. Users are stored in the local smbpasswd file. After changing a user's Unix password, the user cannot access Samba shares. What should the administrator do?

After modifying /etc/samba/smb.conf, which command should be used to verify the syntax before restarting the Samba service?

Which TWO commands can be used to display the routing table on a Linux system?

A Linux server in a DMZ hosts a custom web application that listens on TCP port 8080. The server is also configured with SSH on port 22 for remote administration. Recently, the security team noticed an increase in brute-force attacks against SSH from various external IPs. The server runs Fedora with firewalld as the firewall service. The current firewalld default zone is 'public', and the SSH service is allowed in the 'public' zone. The administrator wants to mitigate the brute-force attacks without blocking legitimate users. Additionally, the administrator wants to ensure that only specific administrative IP addresses can initiate SSH connections, and that SSH connections are rate-limited to prevent flooding. The administrator also needs to keep the web application accessible from any external IP. Which course of action best meets these requirements?

An administrator needs to ensure a kernel module is never loaded, even if requested. Which file should be used?

A laptop user frequently moves between different networks. The administrator wants the DNS configuration to update automatically when the laptop connects to a new network via DHCP. Which service or tool is most appropriate for this task?

A Samba share is configured with 'writable = no'. What does this mean?

A system administrator needs to configure an NFS client to automatically mount an exported filesystem from a remote server whenever a user accesses the mount point. Which configuration approach is most appropriate?

Traffic from the 10.1.1.0/24 subnet is seen leaving through eth1 as intended, but reply traffic from the internet never comes back. What is the most likely cause?

A Samba share is used by macOS clients. File names with special characters (e.g., ©) appear garbled. Which parameter should be added to the share configuration?

Which TWO of the following commands are used to load a kernel module manually at runtime? (Choose two.)

A Samba administrator notices that Windows clients cannot access a shared directory. The share is defined in smb.conf as follows: [shared] path = /srv/samba/shared valid users = @staff browseable = yes read only = no The /srv/samba/shared directory has permissions 755 and is owned by root:staff. Which is the most likely cause of the access issue?

Order the steps to configure a Linux system to use LDAP for authentication.

Refer to the exhibit. A system administrator wants to replace disk sdb1 in the RAID1 array. After physically removing sdb, which sequence of commands should be used?

After installing a new kernel, the system administrator notices that the system boots to the old kernel by default. Which command should be used to update the GRUB configuration to boot the new kernel?

A Linux server with two NICs bonded in mode 1 (active-backup) was working correctly until a switch was replaced. Now, although both interfaces are up, the bond always shows only one active slave, and if that slave fails, traffic does not fail over. The bonding configuration uses miimon=100 and neither arp_interval nor arp_ip_target is set. You run 'cat /proc/net/bonding/bond0' and see that the MII status of both slaves is 'up' but the link failures count is 0 for the backup slave. What is the most likely cause, and which parameter should be adjusted?

An organization requires that all email traffic from their mail server must be encrypted in transit. Which of the following is the most appropriate solution?

Match each RAID level to its description.

An administrator wants to restrict SSH access to a server so that only users from the domain 'example.com' can connect. Which file and syntax should be used with TCP Wrappers?

A company's file server uses NFS to export /data to clients. An administrator configures an NFS client by running 'mount -t nfs fileserver:/data /mnt/data'. The mount succeeds and the user can read files. However, after a network interruption, the client system becomes unresponsive when a user attempts to access /mnt/data. Which action should the administrator take to prevent this issue in the future?

An administrator is configuring nftables to log and drop packets from a specific IP. The rule must be added to the input hook. Which command accomplishes this?

An administrator wants to automatically mount home directories from an NFS server when a user logs in. Which service should be configured?

A small office network uses a Linux server running dnsmasq to provide DHCP and DNS services. The server runs Ubuntu with dnsmasq version 2.80. The configuration file /etc/dnsmasq.conf includes: 'interface=eth0', 'dhcp-range=192.168.1.100,192.168.1.200,12h', and no other DNS-related options. Clients receive IP addresses from the DHCP server and can access the internet. However, clients cannot ping other clients by hostname (e.g., 'ping workstation1' fails with NXDOMAIN). The dnsmasq logs show that DHCP requests are handled and the client hostnames are recorded. The administrator verifies that /etc/hosts contains only the localhost entry. Which of the following is the most likely cause?

A Samba administrator needs to configure a share that allows only the user 'alice' and the group 'developers' to read and write files. Others should have no access. Which two parameters should be set in the share definition? (Choose two.)

A company's Linux router uses iptables. The administrator needs to log all dropped packets (by default policy) before they are dropped. Where should the LOG rule be placed?

Refer to the exhibit. The administrator wants to mount /dev/sdb1 at /data using its UUID. Which /etc/fstab entry is correct?

Which TWO network diagnostic steps should be performed to isolate a problem where a Linux server (IP 10.0.0.10/24) cannot reach a remote server (IP 192.168.1.50/24) while other hosts on the same subnet can reach it? Assume routing is properly configured.

Which of the following is a mail delivery agent (MDA)?

A medium-sized company uses a Linux server as its internet gateway. The server runs Ubuntu 20.04 and has two network interfaces: eth0 (IP 192.168.1.1/24) connected to the internal LAN, and eth1 (DHCP client, obtains IP 203.0.113.10/24, gateway 203.0.113.1) connected to the ISP modem. The server uses iptables for NAT with the rule 'iptables -t nat -A POSTROUTING -o eth1 -j MASQUERADE'. IP forwarding is enabled (net.ipv4.ip_forward=1). Firewalld is running with the default zone set to 'public'. For the past week, internal clients on 192.168.1.0/24 have reported intermittent connectivity to external websites. The administrator notices that during the failures, packets sent to external websites leave the internal network (tcpdump on eth1 shows SYN), but the response SYN-ACK never reaches the client. The administrator checks that the iptables FORWARD chain has a default policy of ACCEPT and no restrictive rules. Which of the following is the most likely cause?

Which THREE of the following are standard steps in compiling and installing a custom Linux kernel from source? (Choose three.)

Which TWO DHCP options are commonly used to provide network configuration to clients? (Choose two.)

Refer to the exhibit. The output shows a DHCP exchange between a client (MAC 00:1a:2b:3c:4d:5e) and a server (192.168.1.1). The client is not obtaining an IP address. What is the most likely reason?

A company runs a mixed environment with Linux and Windows clients. The Samba server is configured as a domain member for authentication. Users authenticate via Active Directory using winbind. Recently, the IT department implemented a new password policy that requires all users to change passwords every 90 days. After the policy took effect, several users report that they cannot access Samba shares from their Linux clients (using smbclient) even though they can log into their Windows desktops with the same credentials. The error message on Linux is 'session setup failed: NT_STATUS_LOGON_FAILURE'. The administrator runs 'wbinfo -a username%password' and it succeeds. What is the most likely cause?

In a Samba domain member server, which file contains the SID to Unix ID mappings?

Which TWO statements about the DHCP client on Linux are correct?

You are troubleshooting a Linux client that is unable to connect to the internet. The client is configured to use DHCP on interface eth0. The output of 'ip addr show eth0' shows that the interface has an IP address 192.168.1.100/24, but there is no default gateway. The output of 'ip route show' shows only the local subnet route. The DHCP server is at 192.168.1.1 and is functioning correctly. You have verified that the DHCP client (dhclient) is running, and the lease file /var/lib/dhclient/dhclient-eth0.leases exists and contains option routers 192.168.1.1. Which of the following commands should you run to resolve the issue?

Order the steps to configure a Linux system as an SSH server with key-based authentication.

You are a system administrator at a small company. The network uses DHCP to assign IP addresses to clients. Recently, some users reported intermittent network connectivity issues. Upon investigation, you notice that the DHCP server is running on a Linux server with the ISC DHCP daemon. The server log shows many 'DHCPREQUEST' messages from a particular MAC address with frequent changes in requested IP addresses. Users with that MAC address are experiencing IP address conflicts and connectivity drops. What is the most likely cause and the best corrective action?

A new user has been added to the LDAP directory, but the user cannot log in. The admin confirms the LDAP server is reachable and the user entry exists. Which of the following is the most likely missing configuration?

A DNS administrator wants to implement DNSSEC on an authoritative zone. Which TWO resource records are essential for DNSSEC?

Which TWO commands can be used to list Samba shares on a remote server?

An administrator needs to configure a BIND DNS server to allow dynamic updates from a specific subnet (192.168.1.0/24) for the zone 'example.com'. The administrator must also ensure that the zone file is updated immediately after a dynamic update. Which configuration accomplishes this?

An administrator wants to disable the graphical splash screen during boot. What change should be made in /etc/default/grub?

What is the recommended way to configure a Linux host to obtain an IP address automatically via DHCP on the eth0 interface?

Based on the exhibit, which command would change the DNS server to 1.1.1.1 for the connection MyConnection?

A DHCP server running on a Linux machine is not leasing IP addresses to clients on a particular VLAN. The server's configuration file includes a subnet declaration for that VLAN, but clients receive only link-local addresses. What is the most likely issue?

During kernel development, a developer modifies only a few source files in a module directory. Which make target should be used to rebuild only that module without compiling the entire kernel?

A system administrator has multiple kernel modules that depend on each other. Module A must be loaded before module B. How can this dependency be ensured automatically when using modprobe?

Which TWO of the following are valid methods to join a Samba server to an Active Directory domain using Samba 4?

An administrator wants to limit the size of the kernel ring buffer to prevent memory overflow. Which kernel boot parameter should be used?

A company runs an NTP server that should only synchronize with trusted upstream servers and provide time to internal clients. Which restrict clause in ntp.conf would best secure the server against unauthorized queries?

An organization uses a Samba server as a standalone file server. The share 'Projects' is configured with browseable = yes and guest ok = no. Users authenticate with local Samba accounts. A new employee needs access but cannot authenticate. The administrator added the user with 'smbpasswd -a newuser' and set a password. When the user tries to connect, they get 'NT_STATUS_LOGON_FAILURE'. The administrator verifies the username and password are correct. smb.conf includes: security = user, passdb backend = tdbsam. What is the most likely cause?

A developer frequently needs to access a remote database server that is only accessible via SSH from a jump host. To simplify access, the administrator wants to create a local port forward so that the developer can connect to localhost:3306 and reach the remote database's MySQL port 3306. Which SSH command achieves this?

A Postfix mail server is configured to use Dovecot SASL for authentication. Users report that they can send emails but are prompted for password repeatedly and see "SASL authentication failed" in the logs. The Dovecot SASL socket is configured correctly. What is the most likely cause?

After adding a new LUN to an existing SAN, the administrator runs multipath -ll but sees the new LUN as 'failed'. The multipathd service is running. What is the most likely cause?

A host on 192.168.2.100 tries to SSH to the firewall's IP address (192.168.1.1). The firewall's input chain policy is drop. Will the SSH connection be allowed?

A storage administrator sees the following output from multipath -ll: 'dm-3 (3600605b0038f1f0019f1f7e00000000) size=10G features='0' hwhandler='0' wp=rw' but the paths are all 'failed'. The scsi devices are listed in /proc/scsi/scsi. What is the most likely cause?

A user reports that the command 'smbclient -L //fileserver' fails with a timeout. What is the most likely cause?

An administrator wants to ensure that a Linux client sends all DNS queries to a specific DNS server without relying on DHCP-provided DNS servers. Which configuration files should be modified?

A Samba server is configured with 'security = ads' and joined to an Active Directory domain. Users report that SIDs are not being resolved correctly. Which service and configuration file are critical for ID mapping?

A system administrator compiled a custom kernel module for a new hardware device. After copying the .ko file to /lib/modules/$(uname -r)/, the module is not loading automatically at boot. What is the most likely cause?

Which iptables command is necessary to allow incoming SSH connections (port 22) from the subnet 192.168.1.0/24 while dropping all other incoming traffic? Assume the INPUT chain has a default policy of DROP.

A financial institution uses a Linux server with a custom application that runs as the 'appuser' and writes logs to /var/log/app/. The security team recently detected that the application is vulnerable to a local privilege escalation via log injection. To mitigate, they decide to implement mandatory access control (MAC) using SELinux. The system is CentOS 7 with SELinux in enforcing mode. The current context of /var/log/app is 'unconfined_u:object_r:var_log_t:s0'. The application should only be allowed to write to logs in that directory, and no other processes should modify them. Which SELinux policy change should be made?

Which THREE configuration directives are necessary to enable Winbind for Active Directory authentication on a Samba domain member?

A packet destined to 192.168.1.100 is sent from this router. Which interface will be used to forward it?

Which TWO of the following are common symptoms of a misconfigured winbind service when Samba is joined to an Active Directory domain?

Which THREE statements about PAM configuration are correct? (Select three.)

Which TWO of the following tools are used to capture and analyze network packets on a Linux system?

Which of the following is the correct command to add an IPv6 address 2001:db8::1/64 to interface eth0?

A system fails to boot due to a corrupted initramfs. Which TWO methods can be used to recover? (Choose two.)

A Samba share is configured with 'valid users = @staff' but users in the staff group still get 'NT_STATUS_ACCESS_DENIED' when accessing the share. The server uses 'security = user'. Which additional configuration is required?

Based on the sshd configuration, user 'charlie' attempts to log in using public key authentication. What will happen?

Which THREE directives are essential for configuring an OpenLDAP client in /etc/ldap/ldap.conf? (Choose three.)

A company has a fleet of servers running a custom Linux kernel version 5.4. They have developed several in-house kernel modules that interface with proprietary hardware. Due to a security vulnerability, the company decides to upgrade all servers to kernel version 5.10. After upgrading the kernel on a test server, the custom modules fail to load with the error 'Invalid module format' or 'disagrees about version magic'. The system administrator must resolve this issue for all servers. The modules are closed-source and cannot be modified easily. The administrator considers the following options. Question: What is the most effective course of action to load the custom modules on the new kernel?

Which THREE commands can be used to display routing information?

An administrator is troubleshooting IPv6 connectivity on a Linux host. The host has an IPv6 address configured on eth0, but cannot ping6 the default gateway. The output of 'ip -6 route show' shows a default route via fe80::1 dev eth0. Which tool should be used to verify that the neighbor discovery process is working?

Match each systemd unit type to its function.

A Linux server with two Ethernet interfaces (eth0 and eth1) has been set up as a transparent bridge using brctl. The bridge is up and shows both interfaces as members. However, hosts connected to eth0 cannot communicate with hosts on eth1. What is the most likely cause?

An administrator needs to create a Linux bridge (br0) and add an Ethernet interface (eth1) to it for KVM virtual machine networking. Which set of commands accomplishes this task?

During boot, a server's video driver causes a freeze. At the GRUB2 menu, the administrator needs to interactively add the kernel parameter 'nomodeset' to the boot entry. Which key should be pressed to access the kernel command line editor?

Which THREE of the following are valid Linux bonding modes? (Choose three.)

During boot, the kernel panics because the root filesystem cannot be mounted. Which kernel parameter should be added at the GRUB prompt to try an alternative root device?

A company uses a Samba server (version 4.12) on Ubuntu 20.04 to provide file sharing for the engineering department. The server has a share [projects] defined in smb.conf with the following parameters: `path = /srv/projects`, `valid users = @engineers`, `read only = no`, `create mask = 0660`, `directory mask = 0770`. All users in the engineers group can authenticate and list the share contents but they report that they cannot create new files or modify existing ones. The command `ls -ld /srv/projects` shows `drwxrwxr-x`, and the directory is owned by root:engineers. The sysadmin has confirmed that the file system permissions on /srv/projects are set to 2775, but the setgid bit does not appear in the ls output. Additionally, users are able to create files in other shares on the same server that are configured similarly. Which of the following is the most likely cause and solution?

A system administrator needs to configure a Linux client to use a specific DNS server for a particular domain. Which file should be modified to achieve this?

An organization uses LDAP for centralized authentication. The /etc/nsswitch.conf contains 'passwd: files ldap' and 'shadow: files ldap'. The /etc/pam.d/system-auth includes 'auth requisite pam_ldap.so' and 'account required pam_ldap.so'. However, users can log in using local accounts but not LDAP accounts. The ldapsearch command works correctly against the LDAP server. Logs show 'pam_ldap: error trying to bind as user (No such object)'. Which configuration change is most likely needed?

A developer has compiled a custom kernel with a new feature. The kernel modules are installed in /lib/modules/$(uname -r)/. However, when the system boots, the kernel fails to load some modules with 'Exec format error'. What is the most likely cause?

A security analyst notices that an /etc/pam.d/common-auth file contains the line 'auth required pam_tally2.so deny=5'. What is the effect?

Arrange the steps to configure a Linux system as an Apache virtual host.

An administrator wants to configure a virtual IP address on interface eth0 with IP 192.168.1.100/24. Which command correctly adds the virtual IP as an alias?

A system administrator is responsible for a production server running a custom-compiled Linux kernel version 5.15. After a routine update of the kernel source and recompilation, the server fails to boot. The error message on the console is: 'Kernel panic - not syncing: No working init found. Try passing init= option to kernel.' The administrator verifies that the root filesystem is intact by booting from a live USB and mounting the root partition. The filesystem contains the usual /sbin/init (symlinked to systemd). The administrator also checks the boot loader configuration and sees that the kernel command line includes 'root=/dev/sda1 ro'. The init binary exists and is executable. Which of the following is the most likely cause of this boot failure?

Which TWO statements about VLAN tagging are correct?

A system fails to boot with a kernel panic: 'Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)'. The administrator suspects the root filesystem is not being detected. Which kernel parameter should be checked first?

Refer to the exhibit. A user in the group 'staff' attempts to access the share 'share' from a Windows client. The user is prompted for credentials and authenticates successfully, but cannot write any files. What is the most likely reason?

Which TWO files are commonly used by Samba for configuration and user authentication? (Choose two.)

In Samba 4, what is the default security mode when no 'security' parameter is set in the [global] section?

An organization is migrating from SysV init to systemd. What systemd command should be used to check the status of the HTTP service?

You are a systems administrator for a company that runs a critical web server on a Linux system. The server has been running stably for months, but after a recent kernel update from version 5.10.0-8 to 5.10.0-9, the server fails to boot. The boot process starts, but after the kernel loads, the system hangs with no output on the console. You have physical access to the server and can interrupt the boot process. The server uses GRUB 2 as the bootloader and the root filesystem is on an LVM logical volume. The previous kernel (5.10.0-8) is still present in /boot. Which of the following is the best course of action to restore the server to a working state?

A company uses NIS for user authentication. A client cannot log in with network accounts but local accounts work. Which command should be used to check if the client is bound to the NIS domain?

A Linux router is experiencing asymmetric routing issues. The network has two internet connections (ISP1 and ISP2) with default routes. The administrator wants to ensure that traffic originating from a specific source IP uses ISP1 for both incoming and outgoing packets. Which ip rule configuration achieves this?

An administrator is configuring a BIND 9 DNS server to support DNSSEC for the zone 'example.com'. The zone is signed using the NSEC3 algorithm. Which TWO statements are correct regarding the configuration and operation of NSEC3?

A Linux client is configured with the following in /etc/nslcd.conf: 'uri ldap://10.0.0.1/', 'base dc=example,dc=com'. Which command can be used to test connectivity to the LDAP server and verify the base DN?

An administrator needs to configure a Linux client to automatically obtain an IP address from a DHCP server but also ensure that the client uses a specific static DNS server (8.8.8.8) regardless of the DHCP-provided DNS. Which configuration should be applied?

Which TWO Samba security modes are considered insecure and should be avoided? (Choose two.)

Arrange the steps to configure a Linux server as an NFS client that mounts a remote export.

Which TWO global parameters can be used to control the security mode of a Samba server?

Which TWO commands can be used to connect to a Samba share from a Linux command line?

A system administrator needs to configure a VPN tunnel using WireGuard. The private key of the local peer is stored in /etc/wireguard/private.key. Which command should be used to set the private key via wg-quick?

Refer to the exhibit. A user reports that they can connect to the 'shared' share from a Windows client and read files, but cannot write any files. The share permissions on the filesystem are set to 777 on /srv/samba/shared. What is the most likely cause of the write failure?

A Linux workstation must be configured to automatically mount an NFS share from server nfs.example.com:/exports/data at boot time. The share should be mounted with noexec and nosuid options. Which line should be added to /etc/fstab?

Match each kernel parameter to its effect.

A system administrator wants to allow incoming SSH connections from only the 192.168.1.0/24 network on a Linux server. Which iptables rule accomplishes this?

Windows clients cannot see the Samba server in Network Neighborhood, but they can access shares by typing the UNC path. Which Samba daemon must be running?

Refer to the exhibit. Which kernel version will be booted by default when using a standard GRUB2 configuration that uses the symlinks vmlinuz and initrd.img?

You are the administrator for a small office network with 20 Linux workstations and 5 Windows 10 clients. The company uses a Samba server (version 4.15) running on Ubuntu 22.04 to share a central directory /data with user-level security. Each user has a home directory on the server, and all users are in the 'staff' group. Recently, users have complained that they can access the /data share from Windows but cannot modify any files, even though they could before. The Samba configuration for the share is: [data] path = /data browseable = yes read only = no valid users = @staff create mask = 0660 directory mask = 0770 force group = staff You check the filesystem permissions on /data and find it is owned by root:staff with permissions 775. Files inside are owned by individual users and group staff with permissions 664. You also check smbstatus and see that users are connected as 'guest' rather than their actual username. What is the most likely cause of the problem?

Which Apache module is used to rewrite URLs based on rules?

A DNS server returns SERVFAIL for queries to a zone that is configured as a slave. The master server is reachable. What should the administrator check?

A system administrator notices that clients on the internal network can resolve the company's web server's hostname (www.example.com) using the internal DNS server (192.168.1.10), but external clients are unable to resolve it. The company uses BIND9 on an Ubuntu server. Which of the following configuration changes should be made on the DNS server to allow external resolution?

Order the steps to configure a Linux system as a DHCP client using dhclient.

A system administrator needs to ensure that a custom kernel module loads automatically at boot. The module is named 'my_driver' and is built for the current kernel. Which configuration file should be modified to ensure the module loads automatically?

Which Postfix configuration parameter specifies the domain that is appended to unqualified email addresses?

An administrator observes that only one path is shown as active for mpathb. What is the most likely cause?

After modifying smb.conf, which command should be used to verify the configuration syntax before restarting Samba?

Which TWO options in dhcpd.conf are used to define the subnet and the address range for dynamic allocation? (Select two.)

To protect against SSH brute-force attacks, a system administrator installs fail2ban. Which configuration file should be modified to enable the SSH jail with default settings?

A system administrator wants to verify the integrity of a downloaded package using a GPG signature. Which command should be used after importing the distributor's public key?

An administrator wants to enhance the security of a web server running Apache. Which TWO of the following actions are recommended best practices?

Which legacy SMB protocol version should be disabled for security best practices on a modern Samba server?

To ensure that OpenVPN clients authenticate the server, which configuration directive should be present on the client side?

In a PAM configuration file, which control flag is used for modules that are not required but can provide additional functionality?

An administrator configures LDAP authentication on a Linux client. After making changes to /etc/nsswitch.conf and /etc/pam.d/system-auth, users can log in but cannot execute commands like 'id username'. What is the most likely cause?

Which two commands correctly configure SSH to disable root login? (Select two.)

Which file is used by the NetworkManager daemon to store connection profiles on a Linux system?

A company's mail server (Postfix) is rejecting incoming emails from a trusted partner with the error '550 5.7.1 Service unavailable; Client host [203.0.113.50] blocked using zen.spamhaus.org'. The partner's IP is not listed on any public DNSBL. What is the most likely cause?

Which two of the following are valid methods to pass kernel parameters during the boot process? (Choose two.)

Refer to the exhibit. An administrator has applied these iptables rules. Users can still SSH into the server from any IP address, which is unexpected because the administrator intended to restrict SSH to only a specific subnet. What is the most likely reason the restriction is not working?

A system administrator needs to create a new 500 MB ext4 filesystem on /dev/sdb1 and mount it persistently at /data. Which set of commands accomplishes this task?

Which TWO statements about LVM thin provisioning are correct?

Refer to the exhibit. A user cannot log in via SSH even though the password is correct. What is the most likely issue?

A web server running Apache httpd is experiencing high load. The administrator suspects that many requests are for non-existent virtual hosts. Which configuration change would reduce the load caused by these requests?

An administrator configures a DHCP relay agent using 'dhcrelay' in a network with multiple VLANs. The relay agent is on a Linux server with interfaces eth0 (VLAN 10) and eth1 (VLAN 20). The DHCP server is on VLAN 10. Which command correctly sets up the relay to forward requests from VLAN 20 to the DHCP server at 192.168.1.5?

A server with a custom kernel fails to boot after a kernel update. The system displays a kernel panic: 'VFS: Unable to mount root fs on unknown-block(0,0)'. The root filesystem is on an LVM volume. What is the most likely cause?

Which file is used by GRUB2 to load the kernel and initramfs?

A web server running Apache is receiving many failed login attempts. Which tool should be used to dynamically block IPs after a configurable number of failures?

A server running Linux with an ext4 filesystem on /dev/sda1 has experienced an unexpected power loss due to a faulty power supply. After replacing the power supply and rebooting, the system fails to mount /dev/sda1 with an error message indicating 'wrong superblock magic number' or 'superblock corrupted'. The administrator recalls that ext4 filesystems have backup superblocks created during mkfs. Using the command 'dumpe2fs /dev/sda1 | grep -i backup' is not possible because the device is not mountable. However, the administrator remembers that for this specific filesystem, a backup superblock is located at block offset 32768 based on the output of 'mke2fs -n' from the original creation. What is the correct course of action to recover the filesystem and mount it?

A Linux server requires several VLAN interfaces on eth0. The network switch expects 802.1Q tagged frames for VLAN 10. Which command correctly creates the VLAN interface?

Given the mount options shown, which of the following events will cause the NFS mount to become unresponsive (hang)?

Given the exhibit, what is the most likely reason for the GPG error, and what is the correct way to fix it permanently?

A system administrator wants to combine two Gigabit Ethernet interfaces of a Linux server into a single logical interface to increase throughput and provide redundancy. Which kernel module should be loaded to support this? (Assume the interfaces are identical and are connected to the same switch.)

An administrator configures a bridge br0 with two ports (eth0 and eth1). The network uses STP. After configuration, packets from a host on eth0 to a host on eth1 are not forwarded. The bridge shows blocking state for one of the ports. What is the most likely cause?

Arrange the steps to configure a Linux system as a DNS server using BIND.

An administrator needs to disable IPv6 on a running system without rebooting and make the change permanent across reboots. Which set of commands should be used?

A system's root filesystem on /dev/sda1 is offline. The administrator boots into rescue mode and needs to check the filesystem integrity. Which command should be used first?

An administrator needs to create a Samba share that allows all users in the 'staff' group read/write access, but denies access to everyone else. Which configuration achieves this?

Which TWO of the following commands can be used to list currently loaded kernel modules? (Choose two.)

Which sysctl parameter controls the system's behavior when a kernel oops occurs (e.g., automatically reboot)?

Refer to the exhibit. A user attempts to access the 'public' share without authentication. What will be the outcome?

Which file is used to configure the LDAP client for system authentication on a modern Linux system using nss-pam-ldapd?

A server with IP 10.0.0.1 needs to forward packets from network 192.168.1.0/24 to 10.0.0.0/24. The administrator runs: 'iptables -t nat -A POSTROUTING -s 192.168.1.0/24 -d 10.0.0.0/24 -j MASQUERADE'. However, traffic from 192.168.1.0/24 cannot reach 10.0.0.0/24. What is the most likely missing configuration?

An administrator configures a Samba share with guest access. After testing, guests are prompted for a password. Which directive should be added to the [global] section to allow guest access without a password?

An administrator configures iptables on a Linux firewall with the following rules: -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT; -A INPUT -p tcp --dport 22 -m state --state ESTABLISHED,RELATED -j ACCEPT; -A INPUT -j DROP. Users report that SSH connections are being dropped. What is the most likely cause?

Refer to the exhibit. What is wrong with the reverse DNS resolution for 192.0.2.1?

Which THREE of the following are valid bonding modes in Linux?

A sysadmin is configuring VLAN tagging on a Linux server that will act as a router-on-a-stick for multiple VLANs (10, 20, 30). The server has a single physical interface enp0s3 connected to a switch trunk port that allows VLANs 10, 20, and 30. The administrator uses systemd-networkd and creates VLAN interfaces enp0s3.10, enp0s3.20, enp0s3.30 with IP addresses 10.0.10.1/24, 10.0.20.1/24, and 10.0.30.1/24 respectively. They enable IP forwarding and, for security, set the iptables FORWARD chain default policy to DROP, but they add no specific rules. Clients in VLAN 10 can ping their gateway (10.0.10.1) but cannot ping clients in VLAN 20 (10.0.20.2). The switch confirms correct configuration. Which of the following is the most likely cause?

Based on the smbstatus output, which statement is true?

Which TWO parameters are used to control Samba's printer sharing? (Choose two.)

Refer to the exhibit. The /data filesystem is nearly full. The administrator has added a new disk /dev/sdc with 10GB capacity. The VG currently has no free space. Which steps will increase the available space for /data using LVM and ext4?

A system with SELinux in enforcing mode is running a custom application that needs to write to a file in /data. The application's context type is 'myapp_t', and the target file context is 'default_t'. The file's current context is 'var_t'. Which command changes the file's context to allow access?

Which command will display the current VLAN membership of interface eth1?

Refer to the exhibit. The user 'user' reports that they are able to run 'sudo apt-get update' without a password, but 'sudo apt-get upgrade' prompts for a password. What is the most likely cause?

An administrator notices that an NFS mount on a client becomes unresponsive when the NFS server goes offline. The admin wants the mount to return an error to the application after a short timeout instead of hanging indefinitely. Which mount option should be added to the fstab entry?

Which command is used to list the NFS exports available from a specific server?

A Samba server experiences slow file transfers for large files. The administrator suspects oplock issues. Which set of parameters should be adjusted to disable opportunistic locking?

A system administrator recently configured two NICs in a bonding interface (bond0) using mode 1 (active-backup). Although both links appear up, traffic never fails over when the primary link goes down. Which command should the administrator use to diagnose the bonding status and determine the root cause?

Based on the ACL output, which user(s) can write to the file /var/www/html/index.html?

A Samba share is configured with 'browseable = yes' but Windows clients cannot see it in the network list. However, they can access it by typing the UNC path directly. Which parameter is most likely misconfigured?

An administrator wants to block all incoming traffic from the IP address 203.0.113.55 except for SSH (port 22) using iptables. The current default policy for the INPUT chain is ACCEPT. Which set of commands achieves this?

Which TWO files are commonly used to configure PAM authentication for the 'login' service on a Linux system? (Choose two.)

An administrator wants to check the ARP cache for a specific IP address 192.168.1.1. Which command will display the ARP entry for that address?

Which three directories or files are typically associated with the Linux kernel? (Choose three.)

A system administrator has compiled a custom Linux kernel (version 5.15.19) with ext4 filesystem support built as a module. The administrator installed the kernel to /boot and built an initramfs using dracut with default options. After rebooting, the system fails with a kernel panic: 'VFS: Unable to mount root fs on unknown-block(0,0)'. The administrator confirms that the root partition is /dev/sda1 formatted as ext4 and that the kernel configuration includes the ext4 module. The kernel command line includes 'root=/dev/sda1' and 'rd.auto'. The administrator also notices that the initramfs file is only 5 MB in size, which seems smaller than expected. Which of the following is the most likely cause and best solution?

A network administrator is configuring source-based routing. They have created a new routing table and added a default route. They then run: ip rule add to 10.0.0.0/24 lookup 100. Traffic from 10.0.0.0/24 still uses the main table. What is the problem?

A mail server running Postfix is deferring messages for a local user. The mail log shows 'status=deferred (mailbox is locked)'. What is the most likely cause?

What is the most likely error in the configuration?

A database server uses LVM with an XFS filesystem on /dev/vg_data/lv_db, mounted at /var/lib/mysql. The LV is at 95% capacity. A new 50GB disk /dev/sdd has been added and initialized as a physical volume, then added to the volume group vg_data. The database is running and cannot be stopped. The administrator must extend the LV and filesystem. What is the correct course of action?

A user reports that they cannot SSH to a remote server using the usual command 'ssh user@remote.example.com'. The administrator tests and gets 'Permission denied (publickey,gssapi-keyex,gssapi-with-mic)'. The user's public key is in ~/.ssh/authorized_keys on the remote server. The local client has the matching private key. Which step should the administrator take to resolve the issue?

Which THREE of the following are correct statements about LVM thin provisioning? (Select THREE)

A Samba share uses the 'acl_xattr' VFS module to store NT ACLs in extended attributes. The administrator runs 'getfattr -d /srv/share/file.txt' and sees no system attributes related to NT ACLs. What is the most likely cause?

A server reports packet loss on a bonded interface (mode 4). The switch configuration is verified correct. Running ethtool shows all slaves are connected at 1 Gbps full duplex. Which command should be used to check if the LACP negotiation is successful?

An administrator is reviewing the audit rules on a Linux server. The current rules are shown in the exhibit. The administrator needs to ensure that any failed attempts to open files are logged, while also monitoring for successful outbound connections. Which of the following describes the effect of the current rules?

Refer to the exhibit. If a user on the local machine tries to SSH to a remote host on eth1, what will happen?

An administrator creates a new XFS filesystem on /dev/vg/data and needs to mount it at /data with noatime and a stripe unit of 1 MiB. Which /etc/fstab entry is correct?

A system administrator notices that the network bond interface bond0 is not operational. The bond is configured using mode 1 (active-backup). The physical interfaces eth0 and eth1 are both up but bond0 shows 'DOWN'. Which of the following is the most likely cause?

After upgrading the kernel on a Red Hat Enterprise Linux system, the system fails to boot because the initramfs is missing. Which command can be used to regenerate the initramfs?

Which directive in dhcpd.conf sets the maximum lease time?

Which TWO tools can be used to configure network interfaces on a Linux system?

A systems administrator is troubleshooting a server that fails to boot after a kernel upgrade. The boot process hangs at the stage where the kernel attempts to mount the root filesystem. Which of the following is the most likely cause?

A Linux client is configured with two network interfaces: eth0 (connected to the internet) and eth1 (connected to a private LAN). The default route is set to eth0. The client can access the internet but cannot access hosts on the private LAN. What is the most likely cause?

Which Samba component provides NetBIOS name resolution and browsing services?

A user needs to run a specific command as root without being prompted for a password. The command is /usr/bin/systemctl restart apache2. Which sudoers rule accomplishes this securely?

During boot, the kernel panics with 'VFS: Unable to mount root fs on unknown-block(0,0)'. Which of the following is the most likely cause?

Which THREE conditions must be met for an SSH key-based login to succeed using the default settings on a OpenSSH server? (Choose three.)

An organization runs a Samba server in standalone mode. They want to allow anonymous (guest) access to a public share. Which configuration option enables guest access for a share?

Order the steps to configure a Linux system to send system logs to a remote syslog server.

Which systemd target is equivalent to the traditional SysV runlevel 3 (multi-user text mode)?

A company has a Samba server configured as a domain member in an Active Directory domain. The server runs Samba 4.13. Recently, Windows clients have been unable to access shares, and the domain join seems broken. The administrator runs 'net ads testjoin' and gets 'Join to domain is not valid'. The smb.conf includes: security = ads, realm = EXAMPLE.COM, workgroup = EXAMPLE. The administrator can successfully resolve the domain controller via DNS. What should the administrator do to fix the issue?

A system administrator needs to ensure that all users must change their passwords every 90 days and that passwords must be at least 12 characters long. The administrator modifies /etc/login.defs and /etc/pam.d/common-password. Which additional step is required to enforce these settings for existing users?

Which TWO of the following are valid ways to map a Windows user to a Linux account in Samba?

A web administrator has installed Apache httpd 2.4 on a Linux server. The default configuration serves files from /var/www/html. When accessing http://server/, the browser shows a directory listing of /var/www/html instead of the index.html file that exists in that directory. The administrator confirms that the user has read permissions on the file and that the file is named index.html. Which directive is most likely missing from the Apache configuration?

Match each network service to its purpose.

Which TWO steps are required to enable IP forwarding on a Linux system permanently?

An administrator runs the command shown. However, when a user tries to execute a binary from /mnt/tmp, it fails with 'Permission denied'. What is the most likely cause?

Which TWO authentication modules can be used with PAM to integrate LDAP authentication on a Linux client?

A system administrator notices that a Linux client is unable to resolve hostnames after connecting to a new network. The client uses DHCP and the /etc/resolv.conf file contains only the loopback address 127.0.0.1. Which of the following is the most likely cause?

A client reports that the [public] share is visible but all files appear read-only. What is the cause?

Which TWO statements about the /etc/hosts file are true?

An administrator needs to create an ext4 filesystem on /dev/sdb1 with a block size of 4096 bytes and reserve 2% of blocks for root. Which command accomplishes this?

Which TWO commands can be used to display the current iptables rules for the filter table?

Which TWO statements are true regarding BIND DNS server security? (Choose two.)

A Linux router is experiencing packet loss for connections that should be forwarded. The router's IP forwarding is enabled, and the routing table is correct. Which kernel parameter is most likely causing the issue?

Match each NFS version to its feature.

A system administrator needs to find out which kernel parameters were passed at boot time. Which command displays the kernel boot parameters?

A Samba share is intended for guest (anonymous) access. Which global parameter must be set to allow this?

A small office uses a Samba server for file sharing. The server is running Samba 4.9 on Ubuntu 18.04. Recently, the administrator added a new user 'john' to the system and added him to the 'staff' group. However, when John tries to access the share 'docs' from his Windows laptop, he gets an 'Access Denied' error. The share configuration is: [docs] path = /srv/docs valid users = @staff read only = No create mask = 0644 directory mask = 0755 The administrator verifies that John is a member of the staff group by running 'groups john' which shows staff. Other users in staff can access the share. What is the most likely cause?

Samba is integrated with Active Directory using security = ads. Which service is required for Kerberos authentication?

A company runs Samba on a Linux server to provide file shares to Windows clients. The server is also a BIND DNS server. After a recent OS upgrade, the Samba service fails to start with the error: 'Failed to create a listening socket for port 445: Permission denied'. The administrator checks that no other service is using port 445. smbd is configured to start as root. What is the most likely cause?

An organization is using Samba as a PDC with an LDAP backend for user accounts. Which idmap backend configuration is appropriate for RFC 2307?

Which TWO parameters in the [global] section are REQUIRED for a Samba server to act as a standalone server (not a member of a domain)?

Hosts connected to eth1 cannot communicate with hosts on eth0. Based on the exhibit, what is the most likely reason?

Which TWO commands can be used to list all currently listening TCP ports and the associated processes?

Which TWO commands can be used to list currently loaded iptables rules in the filter table? (Choose two.)

Which THREE kernel boot parameters can be added to the GRUB command line to enable verbose debug output during boot? (Choose three.)

A system administrator wants to configure a Samba share that grants read-only access to the 'staff' group and full control to the 'managers' group. Which share configuration achieves this?

Which two commands can be used to create a swap space on a partition /dev/sdb2? (Choose two.)

Which three PAM modules can be used to enforce password complexity? (Select three.)

An administrator wants to create a thin provisioned LVM pool and a thin volume. Which sequence of commands is correct?

An administrator configured an autofs direct map for a remote NFS share. The master map at /etc/auto.master contains a line: '/data /etc/auto.direct'. The direct map file /etc/auto.direct has: '/projects -rw,soft fileserver:/exports/projects'. When a user tries to cd /data/projects, it hangs. The autofs service is running. What is the most likely cause?

A filesystem is reported as 'read-only' after an unexpected power failure. Which command should be used to attempt repair without data loss?

A system administrator notices that the SSH service on a Linux server is failing to start. The log shows: 'sshd: error: Could not load host key: /etc/ssh/ssh_host_rsa_key'. What is the most likely cause and solution?

After installing a new kernel on a system using GRUB2, which command should be run to update the boot menu configuration file?

A company develops a custom PCIe device driver as a kernel module. After installing a new kernel version 5.10.50 via a distribution update, the existing driver module fails to load with the error: 'insmod: ERROR: could not insert module mydriver.ko: Invalid module format'. The administrator checks the kernel version and sees that the module was compiled against a previous kernel version 5.10.45. The driver source code is available in /usr/src/mydriver. The administrator needs to get the driver working with the new kernel. Which of the following is the correct course of action?

A system administrator notices that external clients cannot resolve the company's primary website (www.example.com) but internal clients can. What is the most likely cause?

A Samba share is configured with 'force user = jane'. A user 'bob' accesses the share. With what effective user ID will file operations be performed?

A user reports that an external USB hard drive is not detected when plugged in. The system uses a standard kernel with USB support. What is the most likely reason?

Which THREE conditions must be met for a Linux system to act as a router between two networks?

Which command would add the default gateway 192.168.1.1 to this interface?

Which three conditions must be met for a filesystem to be mounted by UUID in /etc/fstab? (Choose three.)

A security audit reveals that the /var/log directory contains world-readable log files that may contain sensitive information. The administrator wants to ensure new files created in /var/log are not readable by others, without affecting existing file permissions. Which umask value should be set system-wide?

An administrator needs to configure iSCSI multipathing. After setting up two paths, which command should be used to verify the multipath topology?

A mail administrator is configuring Postfix to use SASL authentication for incoming connections. Which THREE parameters must be set in main.cf?

Which TWO commands can be used to display the current DNS resolver configuration on a Linux system? (Select TWO.)

A system administrator notices that a new 1TB NVMe drive (/dev/nvme0n1) is not detected by the kernel. The hardware is confirmed working. Which troubleshooting step should be taken first to check if the drive is recognized by the system's PCI subsystem?

Your company has a Linux server acting as a router with three VLAN interfaces: eth0.10 (192.168.10.1/24), eth0.20 (192.168.20.1/24), and eth0.30 (192.168.30.1/24). The server has a default route via eth0 (native VLAN) to the internet gateway at 10.0.0.1. Internal hosts can communicate between VLANs, but cannot reach the internet. You have verified that the default route is present and that the gateway is reachable from the router itself. The iptables FORWARD chain policy is ACCEPT, and no filtering rules are defined. However, you notice that ip_forward is enabled. What is the most likely missing configuration?

Match each Linux boot component to its role.

An administrator uses logwatch to send daily summaries to root. Which configuration file controls the default logwatch behavior?

Which TWO commands display the current kernel routing table? (Choose two.)

Which TWO smb.conf parameters can be used to restrict access to a share based on client IP address or network?

A PAM configuration file for password authentication includes the line 'password requisite pam_cracklib.so retry=3 minlen=8'. A user tries to change their password but is rejected even though the new password meets the stated criteria. The administrator suspects a conflict with another PAM module. Which of the following is the most likely cause?

An administrator is troubleshooting IPv6 connectivity on an interface with link-local address fe80::1. Which command correctly pings that address from the local host, ensuring the packet uses the correct interface?

A company uses Samba to share files from a Linux server to Windows clients. After upgrading Samba from version 4.10 to 4.15, some users report they cannot access shares and receive 'Access denied' errors. The smb.conf has been verified and seems correct. What is the most likely cause?

Given the LDAP client configuration shown in the exhibit, which THREE additional components are required for LDAP authentication to work? (Choose three.)

Refer to the exhibit. A user cannot connect to the 'share2' Samba share. What is the most likely cause?

A Linux server running Samba as a domain member is experiencing slow authentication for users. Which two configuration changes are most likely to improve authentication performance?

A Linux administrator is managing a database server running on CentOS 7 that uses ext4 filesystems on LVM. The server has three physical volumes: /dev/sda (200GB), /dev/sdb (200GB), and /dev/sdc (200GB) all in volume group 'vg_db'. The logical volume 'lv_data' (400GB) is used for database files. Recently, the DBA reports that database writes are slower than expected. Iostat shows high average wait times (>100ms) on /dev/sdc but normal on /dev/sda and /dev/sdb. The LVM stripes data across all three PVs with a stripe size of 64KB. Which action should the administrator take to improve performance?

A Samba server is configured as a classic PDC (Primary Domain Controller) for a legacy network. The administrator needs to add a new machine account for a client joining the domain. Which command accomplishes this?

Your company runs a Samba file server (version 4.15) in a mixed environment with Windows 10 and Linux clients. The server is part of an Active Directory domain. Recently, a new security policy requires that all SMB connections use SMB3 encryption. You have configured 'smb encrypt = required' in the [global] section of smb.conf and restarted smbd. However, Windows clients report that they cannot connect to the server, while Linux clients can connect using mount.cifs with the 'seal' option. You check smb.conf and verify that 'server min protocol = SMB3' is set. What is the most likely cause of the Windows clients' inability to connect?

A Linux client is configured to authenticate users against an LDAP server using PAM. Some users are unable to log in, while others succeed. The admin has verified that the LDAP server is reachable and that the user entries exist. Which of the following is the most likely cause?

Refer to the exhibit. The DNS server at 192.0.2.1 is the primary for example.com. What does the 'lame server' message indicate?

A company has a Linux client running Ubuntu 20.04 that is used by multiple developers. The client has two network interfaces: eth0 (connected to the corporate network with DHCP) and eth1 (connected to a test lab with static IP 192.168.100.10/24). The client needs to access both the internet (via eth0) and the lab network (192.168.100.0/24). The default gateway is 10.0.0.1 on eth0. The lab network has a server at 192.168.100.50 that provides DHCP for the lab devices, but the client's eth1 is statically configured. Recently, the client cannot reach the lab server at 192.168.100.50. The administrator checks the routing table and sees: Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 10.0.0.1 0.0.0.0 UG 100 0 0 eth0 10.0.0.0 0.0.0.0 255.255.255.0 U 100 0 0 eth0 192.168.100.0 0.0.0.0 255.255.255.0 U 100 0 0 eth1 The administrator can ping 192.168.100.50 from the client. However, the lab server cannot ping the client. What is the most likely cause?

Which TWO configuration files are commonly used to specify DNS resolver settings on a Linux system? (Select TWO.)

A company wants to use Samba to share files with Windows clients. Which service must be enabled in Samba to support Windows Active Directory domain membership?

A Samba server is configured to authenticate users against an Active Directory domain using winbind. After joining the domain, some users report that they cannot access shares, while others can. The administrator runs 'wbinfo -u' and sees a list of domain users. However, 'getent passwd' does not show domain users. Which configuration parameter is most likely missing or misconfigured in /etc/samba/smb.conf?

A company runs a critical web server on a custom-built Linux distribution. The server has been stable for months, but after a recent kernel update from version 5.10 to 5.15, the server experiences intermittent crashes. The crashes occur under heavy load and are accompanied by kernel oops messages mentioning a NULL pointer dereference in a network driver. The network driver is a third-party module that was compiled against the old kernel. The system administrator has recompiled the module against the new kernel, but the crashes persist. The server has 64 GB of RAM and uses a bonded network interface with two 10 GbE NICs. The kernel oops trace points to a function in the bonding driver. Which of the following is the most likely cause of the crashes?

A kernel module has been recompiled. Which command updates the module dependency information?

Which two commands display information about LVM physical volumes? (Choose two.)

A DHCP client reports it cannot obtain an IP address. The Ethernet cable is connected and the interface is up. The administrator runs 'dhclient eth0' but gets 'No DHCPOFFERS received'. The network has a DHCP server on the same subnet. Which command should the administrator use next to diagnose the problem?

An administrator is troubleshooting network isolation in a Linux container environment. The container should have its own network stack, but it appears to be using the host's interfaces. Which command correctly runs a command inside a network namespace named 'ns1' to verify its network configuration?

A company runs a database server on Linux with a 4-disk RAID 10 array using mdadm. The server recently experienced a power outage. After reboot, the array is not assembling automatically. The administrator runs `mdadm --assemble --scan` and it fails with a message: 'mdadm: /dev/md0 has been found but is not a valid md superblock.' The administrator checks /proc/mdstat and sees no arrays. The disks /dev/sda, /dev/sdb, /dev/sdc, /dev/sdd are present. Running `mdadm --examine /dev/sda` shows no md superblock, but the disk contains data partitions. The administrator suspects that the superblock may be corrupted or that the disks were accidentally overwritten. The administrator has documentation that the array was created with the following parameters: RAID level 10, 4 disks, chunk size 512 KiB, metadata 1.2. What is the best course of action to recover the array?

A Samba server uses 'security = domain' with an NT4-style domain. After a domain controller outage, users cannot authenticate. Which configuration change would allow fallback to local authentication?

Which TWO daemons are commonly used by DHCP clients on Linux to obtain an IP address? (Choose two.)

Which TWO tools can be used to send test email messages from the command line?

An administrator wants to convert an ext4 filesystem to Btrfs without losing data. Which procedure should be used?

A Samba server is experiencing slow authentication for domain users. The logs show repeated winbind connections to the domain controllers. The administrator suspects that winbind is not caching credentials properly. Which parameter should be checked or increased to improve caching?

Match each security tool to its function.

Arrange the steps to configure a Linux system as a PostgreSQL database server.

A system administrator needs to add a kernel module to the kernel at runtime without recompiling. Which command should be used?

You are the administrator of a medium-sized company that runs its own authoritative DNS servers for the domain 'company.com'. The primary DNS server is a BIND9 master, and there are two slaves. Recently, you updated the zone file on the master to add a new subdomain 'lab.company.com' with an A record pointing to 10.0.0.10. After the update, you increased the serial number and ran 'rndc reload'. However, after several hours, some external clients report that they cannot resolve 'lab.company.com'. You check the master server and find that the zone file contains the new record. You also check the slave servers and find that they still have the old zone data. The serial number on the master is 2025011501, while the slaves show 2025011400. The master's syslog shows no errors. The slaves' syslogs show 'zone company.com/IN: Transfer started.' but no completion messages. Firewall rules allow TCP and UDP port 53 between all DNS servers. What should you do to resolve the issue?

Refer to the exhibit. A user on the client tries to ping 'server1' and gets an unknown host error. What is the most likely cause?

Which TWO are best practices for securing an Apache web server?

A company runs a web application on a Linux server that uses Apache, MySQL, and PHP. The application stores sensitive user data in a MySQL database. The security team has detected that the MySQL service is listening on port 3306 on all interfaces (0.0.0.0). The application and database are on the same server, so there is no need for remote database access. The administrator must secure the MySQL service without breaking the application. Which of the following is the most appropriate course of action?

Which THREE conditions can cause a Linux DHCP client to fail to obtain an IP address? (Select THREE.)

Which THREE are valid values for the 'security' parameter in smb.conf? (Choose three.)

A Samba server is configured as a domain member in an Active Directory environment. Users report that after changing their password on a Windows client, they cannot authenticate to Samba shares. The Samba server is using winbind and the 'idmap_ad' backend. What is the most likely cause?

A client mounts the export with 'mount -t nfs server:/data /mnt/data' and root on the client can write files. Which option in /etc/exports allows root to retain its privileges?

A server with multiple network cards needs a specific kernel module loaded before network configuration. Where should loading be configured for early boot?

To ensure LDAP communication is encrypted, an administrator configures LDAP over SSL (LDAPS) on port 636. Which configuration file on the client should be modified to specify the LDAP server with TLS?

Which TWO are true about the autofs automounter configuration? (Choose two.)

Which TWO conditions must be met for a Linux bridge to forward Ethernet frames between its ports?

To list all currently loaded kernel modules, which command is used?

A technician is troubleshooting a system that fails to boot after adding a new SATA SSD and editing /etc/fstab. The error message is 'Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(8,17)'. What is the most likely issue?

A company has a Linux server with two network interfaces: eth0 connected to the internal 192.168.1.0/24 network, and eth1 connected to the internet via a public IP of 203.0.113.10. The server runs a web server on port 80 and needs to allow internal clients to access the internet while hiding their private IPs (MASQUERADE). Additionally, external users should be able to reach the web server using the public IP. The administrator has enabled IP forwarding and configured iptables with the following rules: iptables -t nat -A POSTROUTING -o eth1 -j MASQUERADE iptables -A FORWARD -i eth0 -o eth1 -j ACCEPT iptables -A FORWARD -i eth1 -o eth0 -m state --state ESTABLISHED,RELATED -j ACCEPT However, internal clients can access the internet, but external users cannot reach the web server. What should the administrator do to fix the issue?

Refer to the exhibit. What does the output indicate about the user John Doe's access to the file report.txt?

During boot, the system displays 'unable to mount root fs on unknown-block'. What is the most likely cause?

An administrator wants to use /dev/sdb for a new ext4 filesystem. Which step must be performed first?

Refer to the exhibit. A system administrator has configured the above in /etc/default/grub. After running update-grub, what will be the boot menu behavior?

An administrator wants to encrypt a file so that only a specific recipient can decrypt it. Which GPG command should be used?

A user authenticates via LDAP successfully, but 'getent passwd' only shows local users. What is the problem?

A company requires link aggregation between a Linux server and a switch to increase throughput and provide redundancy. The switch supports only standard 802.3ad (LACP). Which bonding mode should be configured on the Linux server?

A company runs a high-frequency trading application that requires extremely low latency. The system administrator has compiled a custom Linux kernel with various real-time patches and tuned kernel parameters. After deploying the new kernel, the application performance degrades significantly. The administrator suspects that kernel preemption settings are causing context switch overhead. Which of the following actions should the administrator take to diagnose and optimize the kernel preemption model?

A system has multiple kernels installed. Which command shows the version of the currently booted kernel?

Refer to the exhibit. A client with MAC address 08:00:27:ab:cd:ef on the 192.168.1.0/24 network receives IP 192.168.2.10 instead of an IP from the 192.168.1.0 subnet. What is the most likely explanation?

A Linux router running multiple routing tables is misconfigured. The administrator wants to add a policy routing rule that sends all traffic from subnet 10.10.0.0/16 to routing table 200. Which command should be used?

An administrator needs to configure Samba to allow guest access to a share. Which two parameters must be set?

Which file contains the filesystem table that is read during system boot to mount filesystems?

Which THREE of the following are valid methods to restrict access to the su command on a Linux system?

A company has two BIND DNS servers, a primary and a secondary. The secondary fails to receive zone updates. Which command can be used to check if the primary allows zone transfers to the secondary?

A developer compiled a custom kernel version 5.15.10 and ran 'make modules_install' followed by 'make install' on a system using GRUB 2. After rebooting, the system still boots the old kernel. Which of the following is the most likely cause?

Which three steps are required to build a kernel module from source located outside the kernel tree? (Choose three.)

Which THREE factors can cause a kernel panic during boot? (Select THREE.)

A system administrator wants to allow the user 'jdoe' to run the '/usr/bin/systemctl restart httpd' command on a specific server without a password prompt. Which sudoers entry achieves this?

A data center administrator is troubleshooting a server that hangs during boot after a kernel update. The server uses UEFI and GRUB 2. The administrator observes that the server displays the GRUB menu, selects the new kernel entry, but then the screen goes blank and the system does not respond. The administrator can boot the previous kernel from the GRUB menu successfully. Which of the following is the most likely cause of this issue?

A user wants to mount a Samba share on a Linux client using the command line. Which utility is used for that purpose?

Which two utilities can be used to load kernel modules? (Choose two.)

A system administrator configures a Linux client to authenticate users via an LDAP directory directory for user login. The LDAP server is located on a remote network across a WAN link with moderate latency. Authentication succeeds, but user logins take 10-15 seconds to complete, causing delays. The LDAP server logs show low CPU usage and minimal queries per second. The client has not yet implemented any local caching services. The administrator wants to reduce the login delay without compromising security. What should the administrator do?

A system administrator is troubleshooting a hardware issue that occurs during boot. To monitor the kernel messages in real-time, which command should be run?

Which THREE of the following are correct about RAID 1 in mdadm? (Select THREE)

A user 'bob' is unable to save changes to report.doc. Based on the exhibit, what is the most likely reason?

After modifying /etc/samba/smb.conf, an administrator runs a command to validate the configuration. Which command is correct?

A company runs an Apache web server (port 80) and an SSH server (port 22) for remote administration. The system administrator notices that the server has become sluggish and network traffic has increased significantly. Checking /var/log/auth.log reveals hundreds of failed SSH authentication attempts per minute from diverse IP addresses targeting the 'admin' user. The administrator wants to mitigate this brute-force attack with minimal impact on legitimate users. Which course of action is most effective?

Given the smb.conf exhibit, which share(s) allow write access to user 'alice' who is a member of the 'staff' group?

A system administrator needs to include a custom kernel module in the initramfs to support a root filesystem on a USB device. Which command should be used to rebuild the initramfs with the updated kernel?

Match each LVM term to its definition.

To implement 802.1X port-based authentication on a Linux network interface, which combination of software components is typically required when the Linux system acts as the supplicant?

A small office uses a Linux server running Samba to share documents. The share is accessible but very slow, especially when writing large files. The network is 1 Gbps, and disk performance is fine. The smb.conf has default settings. Which change is most likely to improve write performance?

A system administrator wants to combine two 1 Gbps Ethernet interfaces into a single logical bonded interface to increase throughput and provide redundancy. Which mode of bonding will provide both load balancing and fault tolerance without requiring switch configuration?

A network administrator notices that a Linux router with two network interfaces is not forwarding packets between them, despite having IP forwarding enabled in the kernel. The administrator has verified that the firewall rules are not blocking the traffic. What is the most likely cause of the issue?

A user's SSH public key has been added to '~/.ssh/authorized_keys' on a remote server, but the user is still prompted for a password. Which file permission is most likely causing the issue?

Which THREE of the following parameters can improve Samba file transfer performance under heavy load?

A network administrator wants to improve network performance by bonding two gigabit Ethernet interfaces (eth0 and eth1) on a Linux server. The switch supports IEEE 802.3ad (LACP). Which bonding mode should be used to provide both load balancing and fault tolerance?

Refer to the exhibit. Which kernel parameter is responsible for reducing the amount of kernel messages displayed on the console?

A Linux server exports a directory /data via NFS to a client. The client mounts it with 'mount -t nfs server:/data /mnt/data'. Write operations from the client fail with 'Permission denied' on some files. The server's /etc/exports contains: /data 192.168.1.0/24(rw,root_squash). What is the most likely issue?

A filesystem check on an XFS filesystem reports corruption. What is the recommended way to repair it?

Given the exhibited routing table and rules, what will happen to a packet originating from IP 192.168.10.50 destined to 8.8.8.8?

A Linux server provides file sharing to Windows clients via Samba. The administrator notices that Windows clients are unable to resolve the NetBIOS name of the server. Which two services are essential for NetBIOS name resolution? (Choose two.)

An application running under AppArmor is failing to write to its log directory. The AppArmor profile for the application includes the line '/var/log/myapp/ r,' but not '/var/log/myapp/** rw,'. What is the most likely issue?

Which TWO conditions are most likely to cause 'NT_STATUS_ACCESS_DENIED' when accessing a Samba share?

Match each Linux filesystem feature to its description.

During boot, the kernel outputs a message indicating that a required device driver is not found. Which command can be used to rebuild the initramfs to include the missing driver?

A small business has a single Linux server that serves as both a file server (Samba) and a web server (Apache). The server is directly connected to the internet. Recently, there have been numerous brute-force SSH login attempts. The administrator wants to implement a simple solution to block IP addresses that have more than 5 failed SSH attempts in 10 minutes. The server runs Ubuntu 20.04. Which tool should the administrator use to achieve this with minimal configuration?

A Samba server is configured with 'vfs objects = recycle' to implement a recycle bin. After some time, users notice that deleted files are not appearing in the recycle bin. Which parameter is likely misconfigured?

A Linux server is configured as a DNS resolver with BIND. Users report that they cannot resolve external hostnames. The server can resolve internal names. Which of the following is the most likely cause?

An administrator wants to restrict access to a service using PAM. Which file order determines the authentication flow for a service?

The DHCP client lease file shows a lease for 192.168.1.100. If the client fails to contact the original DHCP server by the rebind time (12:00), what will occur?

A new user needs access to a Samba share. The administrator adds the user to the system with `adduser alice` and then sets up a Samba password. Which command is used to set the Samba password?

A company's security policy requires that all members of the 'developers' group be able to run the command 'systemctl restart httpd' as root using sudo, without being prompted for a password. Which sudoers entry achieves this?

What is the purpose of the 'idmap config * : backend = tdb2' line?

Which two of the following are valid methods to authenticate with OpenVPN? (Select two.)

An AppArmor profile for a database server is too restrictive and denies legitimate queries. The administrator wants to learn the required accesses by running the application in complain mode. Which command puts the profile into complain mode?

An administrator wants to compile a new kernel module that is not yet in the tree. What file should be referenced to ensure the module is built with the same configuration as the current kernel?

Which of the following is a valid NTP configuration file directive to specify a broadcast client?

Based on the iptables output, what is the expected behavior for incoming SSH connections on eth0?

A Linux administrator notices that a newly added disk /dev/sdc is not recognized by the system. Which command should be used to rescan the SCSI bus without rebooting?

An administrator wants to allow user 'john' to execute any command as root without a password. Which sudoers entry is correct?

The administrator wants to create a RAID 1 array using /dev/sdb1 and /dev/sdc1, then create a filesystem and mount it at /mnt/raid1. Which command sequence should be used first?

An administrator is designing a high-availability storage solution using DRBD. The requirement is to have two nodes with synchronous replication and automatic failover in case of primary node failure. Which configuration best achieves this?

Which directive in ntp.conf enables the NTP server to respond to queries from clients?

A system administrator needs to create a RAID 10 array using four disks: /dev/sdb, /dev/sdc, /dev/sdd, /dev/sde. Which TWO commands correctly achieve this?

An organization runs a critical application on a Linux server that stores its data on a 500GB LVM logical volume named /dev/vg_data/lv_app. The application must remain operational with minimal disruption, so unmounting the volume is not acceptable. The administrator needs to create a full backup of the logical volume to an external 1TB USB drive attached via eSATA. The backup must capture a point-in-time consistent state of the filesystem. The logical volume is formatted with XFS. Which of the following procedures best achieves this goal while minimizing downtime?

A company has a server with two network interfaces: eth0 (public IP) and eth1 (private IP). The administrator wants to allow SSH from the public network only. Which iptables rule set achieves this?

Which THREE statements about Samba's 'net' command are true? (Choose three.)

After rebooting, the bridge br0 does not forward traffic between eth0 and eth1. Which configuration is most likely missing?

A security analyst wants to capture only TCP packets with the SYN flag set to identify connection attempts. Which tcpdump filter expression accomplishes this?

Refer to the exhibit. A security audit reveals that the server is not blocking SSH connections from unauthorized networks. What is the most likely cause?

A Linux router needs to forward DHCP broadcasts from clients on subnet 192.168.1.0/24 (eth0) to a DHCP server at 10.0.0.5. Which command starts a DHCP relay agent?

A company requires two-factor authentication for SSH logins. Which PAM module can be used to implement this if the system uses a time-based one-time password (TOTP)?

Which TWO of the following actions are recommended to improve SSH server security?

A company has multiple internet connections and wants to route traffic from specific subnets to specific providers. They are using policy-based routing with ip rule and ip route. After adding the rules, the administrator finds that the traffic is not matching the intended routing table. Which command should be used to verify that the rules are being matched correctly?

An administrator needs to prioritize traffic for a VoIP application over other traffic on a Linux router. Which tool should be used to implement traffic shaping and prioritization?

Which TWO of the following commands can be used to load a kernel module into the running kernel?

A system administrator notices that the default gateway is missing after a reboot. The network configuration uses ifup/ifdown scripts. Which file should be modified to ensure the default gateway is persistent?

A security audit reveals that a server with PAM authentication allows users to log in even when the '/etc/nologin' file exists, contrary to policy. Which PAM module is most likely misconfigured or missing?

A Samba server is configured as a print server. Clients running Windows 10 report that printer drivers cannot be uploaded. The relevant smb.conf section is: [printers] comment = All Printers path = /var/spool/samba browseable = no printable = yes What is the most likely cause?

An administrator wants to restrict access to a Samba share based on client IP addresses. Which parameter in the [share] section of smb.conf should be used?

Which TWO of the following commands are used to manage kernel modules? (Select TWO.)

Which command can be used to create a swap partition on /dev/sdb1?

You are the security administrator for a company that runs a web application on a Linux server. The application runs under the user 'www-data' and listens on TCP port 8080. The server also runs an SSH service on port 22. Recently, an external penetration test revealed that an attacker could exploit a vulnerability in the web application to execute commands as the 'www-data' user, and from there, the attacker could escalate privileges to root due to a misconfigured sudo rule. You need to implement a defense-in-depth approach to limit the impact of such an attack. Which single action would be the most effective in preventing privilege escalation from the 'www-data' user to root, while still allowing the application to function normally?

After creating a new partition table on /dev/sda, what command should be run to install GRUB2 to the Master Boot Record?

A Linux host has a routing table entry that sends all traffic destined for the 10.0.0.0/8 network out interface eth1. A packet is sent from 192.168.1.100 to 10.0.0.5. Which interface will the packet exit?

Which TWO statements about LVM thin provisioning are correct?

Which TWO of the following are recommended best practices for securing a Linux server that is publicly accessible?

A systems administrator is configuring a Postfix mail server to use Dovecot for SASL authentication. The authentication method is set to PLAIN in Dovecot, and Postfix has smtpd_sasl_auth_enable=yes and smtpd_sasl_type=dovecot. Dovecot's auth socket is at /var/run/dovecot/auth-client. The mail logs show repeated "SASL authentication failed" errors for known good credentials. The administrator checks that the socket exists and that Dovecot is running. What is the most likely cause?

An enterprise environment uses Samba as an Active Directory domain controller using Samba 4.11. The administrator needs to configure a read-only domain controller (RODC) for a remote branch office. Which of the following steps is correct?

After adding a new network interface, the system assigns it the name 'enp0s3' instead of 'eth0'. Which of the following best describes the reason for this change?

A system administrator notices that the 'pcspkr' kernel module is causing beeps on the server console. The administrator wants to prevent this module from loading permanently. Which of the following is the correct method to blacklist the module?

Which THREE files are commonly involved in configuring a Linux client for LDAP authentication?

A Postfix administrator wants to restrict which clients can relay mail through the server. Which three smtpd restriction lists are typically used for this purpose? (Choose three.)

A company's network has a single switch connecting all devices. The IT manager wants to isolate the development team's traffic from the rest of the network without buying new hardware. Which configuration should the administrator implement on the switch ports connected to the development team's computers?

A system administrator notices that a new iSCSI target is not appearing as a block device after running iscsiadm. The target is known to be online and reachable. What is the most likely cause?

An administrator needs to extend an ext4 filesystem on logical volume 'home' by 5 GB. The volume group 'vg' has free extents. Which sequence of commands is correct?

An organization's Postfix mail server is being used as an open relay. The administrator wants to restrict relaying to only authenticated users from the internal network. Which combination of settings is correct?

Which three of the following are required steps to compile and install a custom Linux kernel from source? (Choose three.)

A Samba server is configured as above. Users alice and bob have local system accounts but neither can connect to the share. What is the most likely cause?

A company runs a critical database server on a Linux system. The server is subject to a strict compliance policy that requires all commands executed by the database administrator (user 'dbadmin') to be logged. Additionally, any attempt to change the system time must be logged regardless of the user. The administrator has configured auditd and added the following rules: -w /usr/bin -p x -k binary_exec, -a always,exit -F arch=b64 -S adjtimex -F key=time_change. However, during a compliance audit, it is discovered that not all commands executed by dbadmin are being logged. Which of the following is the most likely cause?

To create a simple bridge interface that connects two Ethernet interfaces, which of the following commands should be used?

A Samba server is configured to store NT ACLs on a Linux filesystem that does not support them natively. Which VFS module should be used to map NT ACLs to POSIX ACLs?

A company runs a DNS server using BIND9 on a Linux server. The server is configured with two network interfaces: one internal (192.168.1.10) and one external (203.0.113.10). The server is configured to be authoritative for example.com. Internal clients can resolve example.com, but external clients receive "SERVFAIL" responses. The host command from an external client returns "Host not found". The administrator checks the named configuration and finds the following in /etc/bind/named.conf.options: options { directory "/var/cache/bind"; listen-on { 127.0.0.1; 192.168.1.10; 203.0.113.10; }; allow-query { 192.168.1.0/24; }; recursion no; dnssec-validation auto; }; The zone configuration for example.com has proper allow-transfer and allow-update settings. What change should be made to resolve external queries?

Your company runs a web application on a Linux server that uses Apache HTTPD with mod_ssl for HTTPS. Recently, after a security audit, it was discovered that the server is vulnerable to the POODLE attack on SSLv3. The server is running RHEL 8 with Apache 2.4. The SSL configuration file /etc/httpd/conf.d/ssl.conf currently has the line 'SSLProtocol all -SSLv2'. You need to disable SSLv3 and also disable all versions of TLS below 1.2, while still allowing TLS 1.2 and 1.3. The server must remain available immediately. Which action should you take?

Which of the following is the primary configuration file for the udev device manager?

A system fails to boot with the error shown. Which kernel parameter should be added to the kernel command line to resolve the issue?

You are a network administrator for a medium-sized company. The company has a Linux server acting as a router/firewall with three network interfaces: eth0 (public, 203.0.113.2/24, gateway 203.0.113.1), eth1 (DMZ, 10.0.1.1/24), and eth2 (internal, 192.168.1.1/24). The DMZ hosts a web server with IP 10.0.1.100, and the internal network has client machines. The firewall rules are currently set to default DROP on INPUT and FORWARD, ACCEPT on OUTPUT. The administrator wants to allow internal clients (192.168.1.0/24) to access the web server (10.0.1.100) on port 80. Additionally, the administrator wants to allow external users (from the internet) to access the web server's public IP (203.0.113.2) on port 80, which should be DNATed to 10.0.1.100. The administrator has enabled IP forwarding and added the following rules: iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j DNAT --to-destination 10.0.1.100:80 iptables -A FORWARD -i eth0 -o eth1 -p tcp --dport 80 -j ACCEPT iptables -A FORWARD -i eth1 -o eth0 -p tcp --sport 80 -j ACCEPT Internal clients cannot access the web server. External users are able to access the web server successfully. What is the most likely reason internal clients cannot access the web server?

A company runs a mixed Linux/Windows environment. The Samba server (version 4.15) is configured as a domain member using 'security = ADS'. Recently, the IT team enabled 'winbind use default domain = yes' to simplify logins. After the change, users report that they can no longer access Samba shares when authenticating with just their username (e.g., 'jdoe') instead of 'DOMAIN\jdoe'. However, authentication using the full domain-qualified name still works. The smb.conf includes: [global] security = ADS workgroup = MYDOM realm = MYDOM.LOCAL winbind use default domain = yes winbind separator = / Users are in the 'Domain Users' group and the share configuration is: [share] path = /srv/share valid users = @"MYDOM\domain users" Which of the following is the most likely cause and solution?

A developer compiled a custom kernel, installed it, but the system hangs before init starts. The previous kernel works. Which step was most likely missed?

A client on the internet sends a TCP SYN packet to 10.0.1.10:8080. The router receives it on eth0. According to the exhibit, what will happen to the packet?

A Samba share requires that users must provide valid credentials, but the share should be accessible to any authenticated user without further restrictions. Which security mode should be used?

Which TWO commands can be used to query a DHCP server's lease database on a Linux server running ISC DHCP? (Assume default paths.) (Select two.)

Which TWO tools are commonly used for traffic shaping and QoS on Linux? (Choose two.)

Based on a network capture that shows a TCP connection to port 80 between 10.0.0.1 and 10.0.0.3, which of the following statements is correct?

An administrator wants to chroot SSH users in the 'jailed' group to their home directories. Which configuration in /etc/ssh/sshd_config achieves this?

Which protocol does Samba implement to provide file sharing services to Windows clients?

An administrator needs to encrypt a large file using GPG with a symmetric cipher and then decrypt it on another system. Which command encrypts the file using AES256 and prompts for a passphrase?

Refer to the exhibit. Which module is currently in use by another module?

Which of the following commands creates a new network namespace named 'test'?

Refer to the exhibit. What type of attack is indicated by the log entries?

Arrange the steps to perform a disaster recovery from a full system backup using tar.

Which TWO commands display UUIDs of block devices? (Select TWO)

Refer to the exhibit. An administrator runs aide --check and receives a warning that /var/log/syslog has changed. Why is this expected?

A system administrator wants to change the default kernel boot parameters temporarily to debug a boot issue. Which step should be taken at the GRUB menu to modify kernel parameters for the next boot only?

A BIND9 nameserver is configured with 'allow-transfer { none; };' but a secondary nameserver needs to receive zone transfers. What change must be made on the master?

An Apache administrator is troubleshooting a slow website. Which THREE modules could be causing performance issues if misconfigured?

An Apache web server is experiencing high memory usage under heavy load. The administrator wants to reduce the number of idle child processes. Which configuration directive should be adjusted?

A Linux client is experiencing slow name resolution. The /etc/nsswitch.conf file has the line 'hosts: files dns'. The /etc/hosts file contains many entries. What is the most effective way to improve resolution speed?

An administrator is setting up a Samba share for a project team. The team members are in different UNIX groups. Which three options can be used to restrict access to specific users or groups? (Choose three.)

A web server is running in enforcing mode under SELinux. The administrator wants to allow Apache to connect to a remote database server. Which SELinux boolean needs to be set to allow httpd to make network connections?

Which TWO conditions must be met for a Linux bridge to forward traffic between its ports?

A government agency runs a classified application on a Linux server with strict auditing requirements. The application writes sensitive data to a MySQL database. The auditor requires that all SQL queries executed by the application be logged with timestamps, user, and the full query text. Additionally, the audit logs must be immutable (cannot be altered by the application or any user except a designated auditor account). The database runs on the same server. Which combination of tools and configurations should the administrator deploy?

A filesystem created with mkfs.ext4 on /dev/sda1 has a reserved block count of 5%. How can the administrator reduce it to 1% without reformatting?

Which THREE commands are specifically used to diagnose Samba issues?

A Samba server configured as an Active Directory domain member is unable to authenticate users from the domain. The administrator verifies that DNS resolution works, but `wbinfo -u` returns no output. What is the most likely cause?

Refer to the exhibit. A DNS query for 'ftp.example.com' returns NXDOMAIN. What configuration change would best resolve this?

A DHCP server is configured to serve multiple subnets but only clients on one subnet receive IP addresses. The server is connected to a router that does not forward DHCP broadcasts. What should be configured to support the other subnets?

A Linux client is unable to resolve hostnames for external domains but can ping internal hosts by IP. The /etc/resolv.conf file is correctly configured with a valid DNS server. What is the most likely cause?

Which TWO of the following are effective methods to secure SSH access on a Linux server? (Choose two.)

Which file on a Linux client determines the order in which different name resolution methods (e.g., hosts file, DNS, LDAP) are consulted?

A user in group staff (but not admin) tries to write to the share. What is the most likely error?

Which TWO of the following are valid methods to configure a Linux system to use a specific DNS server for name resolution?

Refer to the exhibit. What is the root filesystem device as specified in the kernel command line?

Which file is used to configure which users and groups are allowed to use the 'cron' daemon?

An LDAP client fails to authenticate users against an LDAP server. The /etc/nsswitch.conf includes 'passwd: files ldap' and the /etc/pam.d/system-auth has appropriate pam_ldap.so entries. However, 'getent passwd' shows only local users. Which command should the administrator run first to diagnose the issue?

A user alice is connected to the 'data' share via smbd, but a file is locked. Which command can forcibly close the file?

An administrator wants to configure Samba to allow only specific users to access a share. Which TWO configuration parameters in smb.conf can be used to restrict access based on usernames?

Refer to the exhibit. The system boots successfully, but the root filesystem is mounted as read-only even after the boot process completes. Which of the following is the most likely cause?

The following output is displayed when running network configuration commands on a Linux system: ``` $ ip link show ... 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel master br0 state UP ... 3: eth0.10@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP ... 4: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP ... $ brctl show bridge name bridge id STP enabled interfaces br0 8000.000000000000 no eth0 ``` Based on this output, what is the configuration of the network interfaces?

Which THREE of the following tools can be used to implement file integrity checking on a Linux system?

A Samba server provides printer sharing using CUPS. Which three global parameters are essential for CUPS integration? (Select THREE)

An administrator is configuring netfilter rules to implement a stateful firewall. Which TWO of the following commands are necessary to allow the firewall to correctly forward TCP traffic from internal to external networks (assuming proper default policies)?

An administrator configures AIDE to monitor /etc. After initializing the database, what command updates the database with current file hashes without removing old entries?

A new network card driver module is not being loaded at boot. The administrator wants to ensure the module is loaded automatically without modifying the kernel command line. Which file should be used?

A system administrator wants to ensure that only key-based authentication is allowed for SSH and password authentication is disabled. Which configuration change is required in /etc/ssh/sshd_config?

Which TWO of the following are valid methods to modify kernel parameters at runtime without rebooting?

A user reports they cannot obtain an IP address via DHCP. The DHCP server logs show no client activity, but the network cable is connected. Which configuration is most likely missing on the DHCP server?

A Linux administrator is setting up an IPsec VPN between two sites using strongSwan. The VPN established successfully, but traffic between the sites is not being encrypted. What is the most probable cause?

A network administrator notices that VLAN tagging is not working on a Linux bridge. The bridge interface br0 has member ports eth0 and eth1. The administrator runs 'bridge vlan show' and sees that only the default VLAN 1 is present. What is the most likely cause?

A company wants to set up a Linux bridge to connect a wireless interface (wlan0) to a wired interface (eth0) to allow devices on the wired network to access the internet through the wireless uplink. The Linux server runs Debian with hostapd to create an access point on wlan0. The administrator creates a bridge br0 using brctl and adds eth0 and wlan0 as ports. They assign IP 192.168.10.1/24 to br0 and start hostapd. Clients on the wired network can access the internet, but cannot ping clients on the wireless network, and vice versa. The administrator verifies that both interfaces are enslaved to br0 (brctl show shows both). They also confirm that IP forwarding is enabled and there are no iptables rules blocking anything. Which of the following is the most likely cause?

An administrator wants to implement network bonding for redundancy on a Linux server running RHEL 8. The server has two physical interfaces em1 and em2. The administrator creates a bond interface bond0 with mode active-backup (mode 1) and adds the slaves em1 and em2. They assign IP address 192.168.50.10/24 to bond0 and bring up the bond. The bond appears to work initially, with one slave active. However, when they disconnect the cable from the active slave, the bond does not fail over to the other slave. The administrator checks /proc/net/bonding/bond0 and sees that the link status for both slaves shows 'up' even after the disconnection. They confirm the bonding module is loaded and the mode is correct. Which of the following is the most likely missing configuration?

A new client with IP 10.0.1.15 tries to connect to HTTPS on the server. Based on the exhibit, what happens?

An administrator notices that clients are unable to obtain IP addresses from the DHCP server. The server logs show 'no free leases' error. What is the most likely cause?

A company is migrating from Apache HTTPD 2.2 to 2.4 and needs to configure SSL for a virtual host. The administrator wants to use modern security practices. Which of the following configurations is the most secure and recommended for Apache 2.4?

A Linux router running FRR (Free Range Routing) needs to participate in OSPF with adjacent Cisco routers. Which configuration file should be modified to enable OSPF?

A company has multiple subnets and wants to implement policy-based routing to direct traffic from a specific development subnet (192.168.10.0/24) through a specialized firewall for content filtering, while all other traffic uses the default gateway. Which of the following steps is required to achieve this using iproute2 tools?

A security policy requires that all users must change their passwords every 90 days. Which command enforces maximum password age for an existing user 'jdoe'?

A company is migrating from a workgroup environment to an Active Directory domain. The Samba server is already configured as a domain member using winbind. The administrator wants to ensure that files created by domain users on the Samba server are owned by the corresponding UNIX user accounts derived from the domain. Which idmap backend and configuration is recommended for this purpose?

A company uses BIND9 as the authoritative name server for its public zone example.com. External users report that they cannot resolve the MX record for the domain, but internal users can. What is the most likely cause?

Which THREE of the following actions are recommended as initial security hardening steps after installing a new Linux server? (Choose three.)

A firewall rule set is implemented using iptables. The administrator wants to allow incoming SSH connections only from the 192.168.1.0/24 subnet, while all other incoming traffic is dropped. Which set of rules achieves this?

A company wants to host multiple websites on a single Apache server with different domain names. Which approach is most appropriate?

An administrator wants to create a chroot environment for a potentially compromised service. The service needs to read /etc/resolv.conf and /etc/hosts, and run from a directory /chroot/service. Which of the following steps is essential to ensure the chroot environment is secure and functional?

Refer to the exhibit. What is the effect of this sudoers configuration?

A Linux system administrator is tasked with upgrading the kernel on a server running a custom compiled kernel (version 4.19) with many in-house modules. The new kernel (5.10) has significant changes, including a different API for some module functions. After compiling the new kernel and the modules, the system boots but some modules fail to load with 'Unknown symbol' errors. The administrator needs to identify which symbols are missing and fix the modules. Which of the following is the most effective approach?

Match each system log to its typical content.

A Samba server is configured with 'security = ads' and joined to an Active Directory domain. Users can authenticate but cannot access shares. The smb.conf includes 'winbind use default domain = yes'. What could be the problem?

Refer to the exhibit. What is the most likely cause of this Apache error?

A database server experiences performance degradation. Analysis shows high I/O wait on a LVM logical volume that uses striping across two physical volumes. What is the most effective way to improve performance?

An administrator wants to drop incoming TCP packets on port 22 from IP 10.0.0.5 using iptables. Which command is correct?

An administrator needs to add support for a new hardware device by compiling a kernel module. After compiling the module against the current kernel source, the module fails to load with 'modprobe: ERROR: could not insert 'mymod': Unknown symbol in module'. Which of the following is the most likely cause?

A system administrator wants to ensure that all commands executed by root are logged to a remote syslog server. Which rsyslog configuration directive should be used?

An administrator configures an NIS client by running 'ypbind' and updating /etc/nsswitch.conf to include 'nis' for passwd, shadow, and group. However, 'getent passwd' still shows only local users. Which step is most likely missing?

Which command can be used to trace the delegation path of a DNS domain?

Order the steps to configure a Linux system as a router using iptables.