LCA Network Configuration & Troubleshooting 2

Question 1

Which command displays the current routing table on a Linux system using the iproute2 suite?

Accepted Answer

ip route show

Answer

The 'ip route show' command from the iproute2 suite displays the kernel routing table.

Question 2

A server cannot reach hosts outside its subnet. The default gateway is set to 192.168.1.1, but pinging it fails. What is the FIRST step to diagnose this?

Accepted Answer

Check if the gateway IP is reachable via ARP using 'arping'

Answer

Using 'arping' confirms whether the gateway's MAC address is reachable at Layer 2 before investigating higher-layer issues.

Question 3

Which file in a Red Hat-based system stores the DNS resolver configuration?

Accepted Answer

/etc/resolv.conf

Answer

The /etc/resolv.conf file specifies nameserver addresses and search domains used by the resolver library.

Question 4

What does the 'ss -tulpn' command display?

Accepted Answer

Listening TCP and UDP sockets with associated process names

Answer

'ss -tulpn' lists all listening (-l) TCP (-t) and UDP (-u) sockets with process names (-p) and numeric ports (-n).

Question 5

You want to add a static route so that traffic to 10.20.0.0/24 goes through gateway 192.168.1.254 permanently on a systemd-networkd system. Where do you configure this?

Accepted Answer

A .network file in /etc/systemd/network/ with a [Route] section

Answer

systemd-networkd reads .network files in /etc/systemd/network/ where [Route] sections define static routes.

(LCA) Certified Linux Administrator Practice Test

(LCA) Certified Linux Administrator Practice Test

LCA Network Configuration & Troubleshooting 2