router:~# ip addr
1: lo: <LOOPBACK,UP,10000> mtu 16436 qdisc noqueue
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth1: <BROADCAST,MULTICAST,UP,10000> mtu 576 qdisc pfifo_fast qlen 1000
    link/ether 00:50:8d:5a:77:b5 brd ff:ff:ff:ff:ff:ff
    inet 12.219.61.253/21 brd 255.255.255.255 scope global eth1
3: eth2: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 1000
    link/ether 00:00:c5:0e:87:04 brd ff:ff:ff:ff:ff:ff
4: eth3: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 1000
    link/ether 00:10:b5:5f:9d:e2 brd ff:ff:ff:ff:ff:ff
    inet 192.168.3.1/24 brd 192.168.3.255 scope global eth3
5: eth4: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc pfifo_fast qlen 1000
    link/ether 00:04:5a:72:9e:6e brd ff:ff:ff:ff:ff:ff
    inet 192.168.4.1/24 brd 192.168.4.255 scope global eth4
    inet6 fe80::204:5aff:fe72:9e6e/64 scope link
       valid_lft forever preferred_lft forever
6: eth5: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 1000
    link/ether 00:04:5a:72:9e:51 brd ff:ff:ff:ff:ff:ff
    inet 192.168.5.1/24 brd 192.168.5.255 scope global eth5
    inet6 fe80::204:5aff:fe72:9e51/64 scope link
       valid_lft forever preferred_lft forever