How do you configure hostname and DNS resolution in Linux?

Set the hostname with hostnamectl set-hostname; name resolution is governed by /etc/hosts (local overrides), /etc/resolv.conf (DNS servers), and /etc/nsswitch.conf (lookup order).

Two related but separate things: the machine's own name, and how it resolves other names. hostnamectl manages the former (and writes it persistently). For resolution, three files cooperate — and /etc/nsswitch.conf decides their priority, which usually means "check /etc/hosts first, then ask DNS".

# View current hostname
hostnamectl

# Set static hostname
hostnamectl set-hostname server01.example.com

# Temporary hostname change
hostname newname

DNS resolution files:

Example /etc/resolv.conf:

search example.com
nameserver 8.8.8.8
nameserver 8.8.4.4

Example /etc/hosts:

127.0.0.1   localhost
192.168.1.10 server01.example.com server01

Tip: NetworkManager overwrites /etc/resolv.conf - use nmcli con mod to set DNS permanently!