ifconfig vs ip
!! ALL of this was stolen from tty1.net. I liked it so much, I decided to copy it for my own reference. !!
/bin/ip has been around for some time now. But people continue using the older command
/sbin/ifconfig. Let's be clear:
ifconfig will not quickly go away, but its newer version,
ip, is more powerful and will eventually replace it.
The man page of
ip may look intimidating at first, but once you get familiar with the command syntax, it is an easy read. This page will not introduce the new features of
ip. It rather features a side-by-side comparison if
ifconfig and ip to get a quick overview of the command syntax.
Show network devices and configuration
ip addr show
ip link show
Enable a network interface
ifconfig eth0 up
ip link set eth0 up
A network interface is disabled in a similar way:
ifconfig eth0 down
ip link set eth0 down
Set IP address
ifconfig eth0 192.168.0.77
ip address add 192.168.0.77 dev eth0
This was the simple version of the command. Often, also the network mask or the broadcast address need to be specified. The following examples show the ifconfig and ip variants.
Needless to say that the netmask can also be given in CIDR notation, e.g. as 192.168.0.77/24.
ifconfig eth0 192.168.0.77 netmask 255.255.255.0 broadcast 192.168.0.255
ip addr add 192.168.0.77/24 broadcast 192.168.0.255 dev eth0
Delete an IP address
With ip it is also possible to delete an address:
ip addr del 192.168.0.77/24 dev eth0
Add alias interface
ifconfig eth0:1 10.0.0.1/8
ip addr add 10.0.0.1/8 dev eth0 label eth0:1
Add an entry in your ARP table.
arp -i eth0 -s 192.168.0.1 00:11:22:33:44:55
ip neigh add 192.168.0.1 lladdr 00:11:22:33:44:55 nud permanent dev eth0
Switch ARP resolution off on one device
ifconfig -arp eth0
ip link set dev eth0 arp off