Linux Networking 4

Question 1

Which command queries a DNS server for information about a domain?

Accepted Answer

dig

Answer

`dig` (Domain Information Groper) queries DNS servers and displays detailed DNS records and responses.

Question 2

What does the `iptables -L` command do?

Accepted Answer

Lists all current firewall rules

Answer

`iptables -L` lists all rules in all chains of the filter table, showing the current firewall policy.

Question 3

Which file configures systemd-networkd or NetworkManager for a network interface on modern systems?

Accepted Answer

/etc/network/interfaces on Debian or /etc/sysconfig/network-scripts/ on RHEL

Answer

Interface configuration lives in `/etc/network/interfaces` on Debian-based systems or `/etc/sysconfig/network-scripts/` on RHEL-based systems.

Question 4

What does setting `net.ipv4.ip_forward=1` in `/etc/sysctl.conf` enable?

Accepted Answer

IP packet forwarding between interfaces, enabling routing

Answer

Enabling `ip_forward` allows the Linux kernel to forward packets between network interfaces, making the host act as a router.

Question 5

Which protocol does DHCP use at the transport layer?

Accepted Answer

UDP

Answer

DHCP uses UDP (ports 67 for server, 68 for client) because clients need to broadcast before they have an IP address.

Linux Practice Test