LPIC-2 Practice Test 31 — 15 Questions

Question 1

Match each Linux filesystem feature to its description.

Accepted Answer

ext4: A journaling filesystem that is the default for many Linux distributions, supporting extents and large files.. The correct matches are ext4 (default journaling filesystem), XFS (high-performance parallel I/O), Btrfs (copy-on-write with snapshots), and F2FS (flash-friendly). Common confusions include swapping ext4 with Btrfs and XFS with F2FS.

Answer

ext4: A copy-on-write filesystem with built-in snapshot and compression capabilities.

Answer

XFS: A flash-friendly filesystem designed for NAND flash storage, minimizing write amplification.

Question 2

Match each system log to its typical content.

Accepted Answer

/var/log/messages: General system messages including kernel and application logs. Correct matches: /var/log/messages -> general system messages, /var/log/secure -> authentication logs, /var/log/maillog -> mail server logs, /var/log/cron -> cron job logs, /var/log/boot.log -> boot logs. Common confusions include swapping definitions of /var/log/messages and /var/log/secure.

Answer

/var/log/messages: Authentication and security related logs

Answer

/var/log/secure: General system messages including kernel and application logs

Question 3

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

Accepted Answer

Procmail. Procmail is a classic mail delivery agent (MDA) that receives messages from a mail transfer agent (MTA) and delivers them to a user's local mailbox, often applying filtering rules based on recipes. It operates after the MTA has accepted the message, making it the correct choice for an MDA.

Answer

Postfix

Answer

Dovecot

Answer

Sendmail

Question 4

Which TWO statements about LVM thin provisioning are correct?

Accepted Answer

It allows creating logical volumes that can be larger than the available physical storage.. LVM thin provisioning allows creating logical volumes that appear larger than the available physical storage (overcommitment). This is achieved by allocating data blocks on demand from a thin pool, rather than reserving them at creation time. The thin pool itself must have sufficient physical storage to accommodate actual writes, but the logical volume size can exceed the pool's capacity.

Answer

Thin pools automatically extend when they reach 80% usage.

Answer

A thin pool cannot be extended once created.

Answer

It is only supported on SSDs.

Question 5

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?

Accepted Answer

dmesg -w. `dmesg -w` (or `dmesg --follow`) provides real-time monitoring of kernel ring buffer messages, which is essential for troubleshooting hardware issues during boot. The `-w` flag waits for new messages and prints them as they appear, similar to `tail -f`, but specifically for kernel messages. This command directly accesses the kernel ring buffer via `/dev/kmsg`, ensuring you see hardware-related errors, driver messages, and device initialization logs as they occur.

Answer

journalctl -f

Answer

tail -f /var/log/kern.log

Answer

less /var/log/messages

Question 6

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

Accepted Answer

make menuconfig. `make menuconfig` is a standard step that launches a text-based menu-driven interface for configuring kernel options before compilation. This step allows the user to select which features, drivers, and modules to include in the kernel build, generating the `.config` file that guides the subsequent compilation.

Answer

make modules_install

Answer

make oldconfig

Question 7

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?

Accepted Answer

The client's /etc/dhcp/dhclient.conf contains a 'reject' statement that rejects offers from this server.. The DHCP client can be configured with a 'reject' statement in /etc/dhcp/dhclient.conf to ignore offers from specific servers. In this scenario, the client sends a DHCPDISCOVER, receives a DHCPOFFER from 192.168.1.1, but then does not proceed to DHCPREQUEST, indicating the offer was rejected locally. This matches the behavior of a reject rule, which causes the client to discard the offer without further communication.

Answer

The DHCP server did not receive the client's request.

Answer

The DHCP server is not reachable from the client.

Answer

The client's MAC address is not authorized on the DHCP server.

Question 8

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

Accepted Answer

Alice has the file open with a deny-write lock.. The exhibit shows that Alice has the file open with a deny-write lock, which prevents any other user (including Bob) from writing to the file. In Samba, this is enforced by the share mode locking mechanism, where a deny-write share access request from Alice blocks subsequent write attempts by Bob until Alice closes the file.

Answer

The oplock is set to NONE causing conflicts.

Answer

Bob does not have permission on the filesystem.

Answer

The share is configured as read-only.

Question 9

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.)

Accepted Answer

bonding. The bonding kernel module (bonding) is the correct choice for combining two Gigabit Ethernet interfaces into a single logical interface to increase throughput and provide redundancy. Bonding is a standard Linux kernel module for link aggregation that supports various modes (e.g., active-backup, 802.3ad). On LPIC-2, bonding is the expected technology for interface bonding.

Answer

bridge

Answer

teaming

Answer

802.1q

Question 10

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

Accepted Answer

Run 'make modules_install' to install compiled modules. After building kernel modules with 'make', you must run 'make modules_install' to copy the compiled modules into the appropriate directory under /lib/modules/$(uname -r)/, making them available for the kernel to load. This step is essential for any kernel that uses loadable modules, as it populates the module tree with the correct .ko files.

Answer

Run 'update-grub' to regenerate GRUB configuration

Answer

Run 'depmod -a' to generate module dependencies

Question 11

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?

Accepted Answer

Run `fsck.ext4 -b 32768 /dev/sda1` to restore the superblock, then mount the filesystem.. `fsck.ext4 -b 32768` instructs the filesystem check utility to use the backup superblock located at block offset 32768, which is a known backup location for ext4 filesystems created with default settings. This allows `fsck` to read a valid superblock, repair the primary superblock, and make the filesystem mountable again without data loss.

Answer

Run `e2fsck -fy /dev/sda1` to force a filesystem check.

Answer

Run `dd if=/dev/zero of=/dev/sda1 bs=4k count=1` to zero the superblock, then create a new filesystem with mkfs.ext4.

Answer

Run `tune2fs -j /dev/sda1` to add a journal to the filesystem.

Question 12

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?

Accepted Answer

Install and configure fail2ban to block IP addresses after 5 failed SSH attempts within 10 minutes.. Fail2ban is specifically designed to mitigate brute-force attacks by monitoring log files (e.g., /var/log/auth.log) for repeated failed authentication attempts and dynamically updating firewall rules (e.g., iptables or nftables) to block offending IP addresses. This approach is automated, reduces manual intervention, and has minimal impact on legitimate users since only IPs exceeding the threshold are blocked.

Answer

Change the SSH port to a non-standard port number.

Answer

Disable password authentication for SSH and use key-based authentication only.

Answer

Add the offending IP addresses to /etc/hosts.deny manually.

Question 13

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?

Accepted Answer

Set 'write cache size = 262144'.. The 'write cache size' option enables a per-file write cache in Samba that buffers write operations before committing them to disk. With default settings, Samba may perform synchronous writes for each chunk, causing severe slowdowns on large file transfers. Setting a write cache size (e.g., 262144 bytes) allows Samba to aggregate writes, dramatically improving throughput on a fast network with adequate disk performance.

Answer

Set 'strict sync = yes'.

Answer

Set 'use sendfile = yes'.

Answer

Set 'socket options = TCP_NODELAY IPTOS_LOWDELAY'.

Question 14

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?

Accepted Answer

The default gateway on the router is not set correctly.. A Linux router needs a default gateway to forward packets to networks not directly connected to any of its interfaces. Even with IP forwarding enabled and no firewall blocking, if the default gateway is not set or is incorrect, the router will drop packets destined for remote networks. The administrator has verified that firewall rules are not blocking traffic, and ARP cache issues would not cause persistent failure, so the most likely cause is a missing or incorrectly configured default gateway.

Answer

The ARP cache on the router is stale.

Answer

The iptables FORWARD chain policy is set to DROP.

Answer

The routing table does not contain a route for the destination network.

Question 15

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?

Accepted Answer

0660. SSH's authorized_keys file must have strict permissions to prevent unauthorized modifications. The correct permission is 0600 (owner read/write only) or more restrictive. Permission 0660 (group read/write) is too permissive because it allows group members to modify the file, which SSH interprets as a security risk and falls back to password authentication.

Answer

0644

Answer

0444

Answer

0600