Linux provides “ifconfig” command to configure network interfaces.

To display list of available interfaces:

[root@techpulp ~]# ifconfig
eth0      Link encap:Ethernet  HWaddr 00:65:23:5E:D4:3C
inet addr:192.168.191.1  Bcast:192.168.191.255  Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
RX packets:261958 errors:0 dropped:0 overruns:0 frame:0
TX packets:201967 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:322195982 (307.2 MiB)  TX bytes:18627969 (17.7 MiB)
Interrupt:21 Base address:0x2000

lo        Link encap:Local Loopback
inet addr:127.0.0.1  Mask:255.0.0.0
UP LOOPBACK RUNNING  MTU:16436  Metric:1
RX packets:4 errors:0 dropped:0 overruns:0 frame:0
TX packets:4 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:240 (240.0 b)  TX bytes:240 (240.0 b)

[root@techpulp ~]#

To bring down an interface “eth0″:

[root@techpulp ~]# ifconfig eth0 down

To bring up an interface “eth0″:

[root@techpulp ~]# ifconfig eth0 up

To configure an interface with an IP address:

[root@techpulp ~]# ifconfig eth0 192.168.191.1 netmask 255.255.255.0 up

(or)

[root@techpulp ~]# ifconfig eth0 192.168.191.1/24 up