Essential System Services and Networking

A DHCP server assigns IP addresses to clients, but some clients are not receiving the correct gateway. Which configuration file should be checked on the DHCP server?

An administrator wants systemd-journald logs to persist across reboots. What must be created?

An Ubuntu 20.04 server needs a static IP address. The administrator has created a netplan YAML file at /etc/netplan/01-netcfg.yaml. What is the next step to apply the configuration?

A company manages a cluster of 50 web servers running Ubuntu 20.04. The servers are configured to synchronize time with an internal NTP server at 10.0.0.100 using the default ntpd. The NTP server itself syncs with external stratum 2 servers. Recently, the security team implemented a restrictive iptables firewall on all servers, allowing only essential services. Several servers in the 10.0.1.0/24 network now report time drift and ntpq -p shows all peers with '?' status. A network engineer runs tcpdump on one affected server and sees no NTP replies from 10.0.0.100. The NTP server's firewall is configured to allow inbound NTP from 10.0.0.0/24 only. The engineer also notes that the server's /etc/ntp.conf contains the line 'restrict 10.0.0.100' (which is incorrect) and that ntpq -crv shows 'sync target not reachable'. Which single action will most directly resolve the synchronization issue for the affected servers?

On a modern Linux system using systemd-networkd for interface management and systemd-resolved for DNS, which THREE files are typically involved in network configuration and DNS resolution?

Refer to the exhibit. The administrator wants to ensure that SSH service starts automatically after a system reboot. Based on the output, what is the current status of this setting?

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

A developer asks the system administrator to configure a local web server for testing using Apache. The server should serve files from /var/www/test. Which directive must be set in the Apache configuration to set this document root?

A company runs a web server using Apache with multiple virtual hosts. The administrator needs to restrict access to a specific virtual host based on the client IP address. Which configuration directive should be placed inside the <VirtualHost> block to deny IP 192.168.1.100?

Refer to the exhibit. The system has two network interfaces: eth0 and eth1. Which interface will be used to reach a host at IP address 10.10.10.10?

Based on the exhibit, what is the most likely cause of the SSH service failure?

Which THREE of the following are true regarding the use of systemd-networkd for network configuration? (Choose three.)

Refer to the exhibit. An administrator runs ss -tuln and gets the output above. Which of the following statements about this server is true?

After a reboot, a server fails to obtain an IP address on its sole ethernet interface. The administrator checks /etc/netplan/01-netcfg.yaml and finds the configuration looks correct. However, the interface shows no IP. The system uses systemd-networkd. Which command should be run next to apply the configuration and bring up the interface?

An administrator needs to monitor real-time network bandwidth usage on a Linux server. Which two tools are specifically designed for this purpose? (Choose two.)

On a Debian-based system using ifupdown, which file should be edited to configure a static IP address for an interface?

A system administrator notices that the system time is incorrect by several minutes. Which command should be used first to check the status of NTP synchronization?

An administrator notices that SSH connections to a remote Linux server are timing out. After confirming network connectivity, which command should the administrator run on the server to check whether the SSH daemon is actively listening?

Which TWO of the following are valid methods to configure network interfaces on a Linux system? (Choose two.)

Which THREE steps are required to configure a static IP address on a modern Linux system using systemd-networkd?

Which three files are essential for network configuration and name resolution on a typical Linux system? (Choose three.)

Which TWO commands can be used to display the current firewall rules in a system using nftables? (Choose two.)

A web server running Apache on Linux is experiencing slow response times. The administrator runs 'netstat -tuln' and sees many connections in TIME_WAIT state. Which of the following is the best course of action to improve performance?

Refer to the exhibit. The administrator is unable to SSH into the server (TCP port 22) from a remote host. The iptables rules are as shown. What is the most likely cause?

Which TWO tools can be used to query DNS records? (Choose two.)

Which two commands can be used to send a test email from the command line to verify SMTP functionality? (Choose two.)

A Linux system's hostname resolution does not consult /etc/hosts before querying DNS. Which file controls the order of name resolution services?

A company's server administrator needs to replace an existing DNS server (192.168.1.10) with a new one (192.168.1.20). Which file must be updated on all DHCP clients to ensure they use the new DNS server?

An administrator reviews the above DHCP server logs. Based on the output, which statement is correct about the DHCP transaction?

Refer to the exhibit. A system administrator runs 'ip route show default' and gets this output. What does it indicate?

A mail server using Postfix is rejecting emails from a partner domain. The administrator checks the maillog and sees 'relay access denied'. Which Postfix configuration parameter is most likely misconfigured?

Which THREE steps are required to configure a network interface with a static IP address using the ip command (assuming interface eth0)? (Choose three.)

A server runs systemd-resolved and uses a VPN. DNS queries fail intermittently. The administrator checks /etc/resolv.conf and finds it is a symlink to /run/systemd/resolve/stub-resolv.conf. Which command should be used to view the effective DNS servers and debug the issue?

A system administrator notices that the system clock is consistently 5 minutes ahead of the actual time. The NTP service is enabled and running. Which command should the administrator run to force an immediate time synchronization?

After running 'ip route show default', a system administrator sees no output. Users on that system can only communicate with hosts on the local subnet. What is the most likely cause?

A technician is troubleshooting network connectivity. The server's IP is 192.168.1.10/24, and the gateway is 192.168.1.1. The server can ping the gateway but cannot ping 8.8.8.8. Which command is most appropriate to check if the default route is configured?

A system administrator notices that the NTP service on a Linux server is not synchronizing time with external NTP servers. The administrator runs 'ntpq -p' and sees that all servers listed have a 'reach' value of 0. Which of the following is the most likely cause?

Refer to the exhibit. The administrator expects logs to be sent to a remote syslog server at 192.168.1.100 on UDP port 514. However, no logs are being received at the remote server. Which is the most likely issue?

On a Linux server using systemd and Postfix for email service, an administrator needs to diagnose a delivery failure for a local user. Which command should be used to view the most recent mail-related system journal entries?

Refer to the exhibit. A system administrator notices that remote SSH connections are being blocked from all IP addresses except 10.0.0.5. Which configuration change would allow SSH from any IP?

Match each Linux command to its primary function.

A small business runs a web application on a Linux server that uses Apache to serve dynamic content via PHP-FPM. The server currently uses the default Apache configuration, but the administrator wants to improve security by limiting access to the server's administrative interface (located at /admin) to only the local network (192.168.1.0/24). The administrative interface is accessed via a separate VirtualHost on port 443. The administrator has created a new VirtualHost configuration file for the admin site. However, after reloading Apache, users from outside the local network can still access the /admin page. The administrator has verified that the VirtualHost is being parsed and that mod_authz_core is enabled. Which of the following actions would most likely resolve the issue?

A system administrator is configuring a Linux server to act as a router. The server has two network interfaces: eth0 (192.168.1.1/24) and eth1 (10.0.0.1/24). Which of the following commands enables IP forwarding on this server?

An administrator is troubleshooting a DNS issue. The command 'dig @8.8.8.8 example.com' returns a response, but 'host example.com' returns 'Host not found'. Which of the following is the most likely cause?

A Linux server running multiple virtual hosts on Apache suddenly becomes unresponsive to web requests. The administrator finds that the server still responds to ping. Which diagnostic command would best identify whether Apache is accepting connections?

Refer to the exhibit. A system administrator finds this line in /etc/rsyslog.conf. What is the effect of this configuration?

Which of the following commands will display the default gateway of a Linux system?

An organization's DNS server (BIND) is authoritatively serving the example.com zone. The administrator needs to add a mail exchange record for mail.example.com with priority 10. Which resource record should be added to the zone file?

Which TWO commands are commonly used to start, stop, or restart system services on a Linux system that uses systemd as its init system?

A company runs a critical web application on a Linux server (Ubuntu 20.04) with Apache and MySQL. The server has two network interfaces: eth0 (public IP) and eth1 (private IP). Recently, the application has been experiencing intermittent connectivity issues. Users report that the web page sometimes loads slowly or times out. The administrator checks the network configuration and finds the following: eth0 is configured with a static IP 203.0.113.10/24, gateway 203.0.113.1; eth1 is configured with a static IP 10.0.0.10/24, no gateway. The administrator runs 'ip route show' and sees: default via 203.0.113.1 dev eth0, 10.0.0.0/24 dev eth1 proto kernel scope link src 10.0.0.10 metric 100. The administrator also notices that the system's /etc/resolv.conf contains nameserver 8.8.8.8 and nameserver 8.8.4.4. The MySQL server is configured to listen on 127.0.0.1. What is the most likely cause of the intermittent connectivity issues?

A sysadmin is troubleshooting a connectivity issue between two servers in different subnets. The output of 'traceroute 192.168.2.10' shows packets reaching a router but not the destination. The router's firewall uses iptables. Which rule would prevent the traceroute from completing?

Which TWO configuration files are commonly associated with NTP client configuration?

Which TWO commands can be used to display network interface statistics on a Linux system?

A host on the 192.168.1.0/24 network cannot reach the internet. Based on the exhibit, which is the most likely cause?

A small office has a network printer with IP 192.168.1.100. The printer is shared via CUPS. A user reports that they cannot print a document from their workstation. The printer appears in the list of available printers, but when they try to print, the job hangs in the queue with status 'processing'. The administrator suspects the printer may be offline or the CUPS service is not running. Which command should the administrator run first to gather diagnostic information about the printer and its queue?

A server in a corporate network uses systemd-resolved for DNS. Internal hostnames (e.g., server.example.lan) fail to resolve, but external names (e.g., google.com) work. The /etc/resolv.conf is a symlink to /run/systemd/resolve/stub-resolv.conf. The administrator checks the systemd-resolved configuration and finds that the internal DNS server is listed globally, but the network interface has no specific DNS set. Which command should be used to assign the internal DNS server to the interface and fix resolution?

Order the steps to mount an NFS share from a remote server.

A user submitted a print job to a CUPS printer but used the wrong options. Which command should the administrator use to cancel the job?

A sysadmin notices that after modifying iptables rules, the SSH service is unreachable from a specific subnet (192.168.1.0/24). Which command should be used to view the current rules with line numbers for easier identification?

An organization wants to implement a centralized logging solution for multiple Linux servers. Which service should run on the central server to receive syslog messages?

A web server running on this host is not accessible from clients. Based on the exhibit, what is the most likely reason?

A user reports that they cannot connect to a remote server using SSH. The administrator checks the SSH server status and it is running. Which of the following is the most likely cause?

A user reports that they cannot access the company's web server. The administrator confirms the server is running and network connectivity is fine. Which command should be used to verify that the HTTP service is listening on the correct port?

A system administrator wants to monitor network traffic on a specific port (TCP/443) entering the server. Which command will capture packets on interface eth0 and display them in real-time?

A junior system administrator is tasked with setting up a new Linux server that will act as a network time client. The server must synchronize its clock with the external NTP pool servers 0.pool.ntp.org, 1.pool.ntp.org, and 2.pool.ntp.org. The administrator installs the ntp package and edits /etc/ntp.conf to include the following lines: server 0.pool.ntp.org server 1.pool.ntp.org server 2.pool.ntp.org However, after restarting the ntpd service, the administrator notices that the system time does not appear to be synchronized. The command 'ntpq -p' returns no output. The administrator checks the status of the ntpd service with 'systemctl status ntp' and sees that the service is active (running). What is the most likely reason for the synchronization failure?

An administrator is configuring a DHCP server to assign IP addresses to clients in the 192.168.10.0/24 subnet. The server should provide the default gateway as 192.168.10.1 and DNS server as 8.8.8.8. Which option in /etc/dhcp/dhcpd.conf defines the default gateway?

An administrator wants to combine two network interfaces into a single logical interface for redundancy and increased throughput. The system uses NetworkManager. Which method is currently recommended to achieve this?

A system administrator notices that the system time is slowly drifting from the actual time. The system uses chrony for NTP synchronization. The administrator runs 'chronyc sources' and sees no reachable sources. The firewall is enabled and configured. Which action should the administrator take to resolve the time synchronization issue?

Which THREE of the following are valid files or directories used by the Domain Name System (DNS) resolution process on a Linux system?

A system administrator wants to configure NTP client on a server running systemd and using systemd-timesyncd. Which file should be edited to set the NTP server?

After updating the SSH configuration, a sysadmin restarts the sshd service, but remote connections still use the old settings. Which command should be used to reload the configuration without dropping existing connections?

A security administrator needs to allow SSH access from the 10.0.0.0/8 network but deny all other traffic to port 22. The firewall uses iptables with default policy ACCEPT on the INPUT chain. Which set of rules should be added?

A company is deploying a new web application and needs to ensure high availability. They have two web servers and want to use DNS round-robin. Which DNS record type is most appropriate?

A database server on a Linux system is configured to listen on TCP port 3306. The administrator wants to restrict access to the database server to only the local network (192.168.1.0/24) using iptables. Which of the following iptables rules achieves this?