Run dhclient on Startup in Ubuntu 18.04

ubuntu-run-dhclient-on-startup.md

dhclient is the Dynamic Host Configuration Protocol (DHCP) Client one would use to allow a client to connect to a DHCP server.

$ sudo nano /etc/rc.local

#!/bin/bash
dhclient
exit 0

$ sudo chmod 755 /etc/rc.local

$ sudo systemctl enable rc-local

$ sudo systemctl restart rc-local

$ sudo systemctl status rc-local

Ubuntu 18.04 (server) is using systemd-networkd as default, if the service is enable systemctl status systemd-networkd, the proper way to enable dhcp is to use the systemd network configuration files (/etc/systemd/network/*) https://www.freedesktop.org/software/systemd/man/systemd.network.html

As exemple, the following configuration file will enable DHCP to any nic that have a name that's matching enp*

cat /etc/systemd/network/20-dhcp.network
[Match]
Name=enp*

[Network]
DHCP=ipv4

Awesome!
Had to do that for the Cloud Image of Ubuntu Server 22.04 LTS (Jammy)

Then later sudo systemctl daemon-reload && sudo systemctl enable systemd-networkd --now