3. dhclient

We've discussed DHCP before and most often you will never need to statically set your IP addresses, subnet masks, etc. Instead you'll be using DHCP! The dhclient starts up on boot and gets a list of network interfaces from the dhclient.conf file. For each interface listed it tries to configure the interface using the DHCP protocol.

In the dhclient.leases file, dhclient keeps track of a list of leases across system reboots, after reading dhclient.conf, the dhclient.leases file is read to let it know what leases it's already assigned.

To obtain a fresh IP

$ sudo dhclient