linuxexpert-practice-labs/labs/rhcsa/8-2-hostname-resolution

RHCSA 8.2: Hostname resolution

The hostname, a name in /etc/hosts, and a DNS server and search domain set the NetworkManager way.

Before you start

The lab gives this VM a spare network interface, eth1, cabled to a small lab network, 192.168.50.0/24, with a profile called eth1 that gives it the address 192.168.50.10/24 and no DNS settings. It comes back at every boot. Your SSH connection doesn't use it: set DNS on the eth1 profile, and leave the main interface's profile alone. A DNS server on eth1 ranks below the main interface's (the lab sets that up in /etc/NetworkManager/conf.d/), so name lookups keep working.

The lab notes your hostname and puts it back when you reset it.

Tasks

1. Set the hostname to server1.example.com, persistently.
2. Make the name web1 (and web1.example.com) resolve to 192.168.50.20 on this system only, so that getent hosts web1 prints 192.168.50.20 web1.example.com web1.
3. Make the system use DNS server 192.168.50.1 and search domain example.com (on the eth1 profile), so that after nmcli connection up and a reboot, /etc/resolv.conf has nameserver 192.168.50.1 and search example.com.

Hints

• hostnamectl set-hostname; hostname, hostname -s.
• /etc/hosts: address, full name, then the short name.
• nmcli connection modify eth1 ipv4.dns ... ipv4.dns-search ..., then nmcli connection up eth1. Don't edit /etc/resolv.conf by hand: NetworkManager rewrites it.