root@ubuntu:/var/www/mrtg# ip addr add 91.201.156.226/28 dev eth1
root@ubuntu:/var/www/mrtg# ifconfig eth1
eth1 Link encap:Ethernet HWaddr 00:40:f4:36:64:13
inet addr:192.168.180.44 Bcast:192.168.180.47 Mask:255.255.255.240
inet6 addr: fe80::240:f4ff:fe36:6413/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:695729 errors:27 dropped:0 overruns:0 frame:0
TX packets:553307 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:240616841 (229.4 MB) TX bytes:103308387 (98.5 MB)
Interrupt:21 Base address:0xd400
Комманда выполнилась.. но на интерфейсе не показывает изменений... хм.
Используйте ip addr show. ifconfig уже признан устаревшим
root@ubuntu:/var/log/mrtg# ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> 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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc htb qlen 1000
link/ether 00:48:54:55:95:e9 brd ff:ff:ff:ff:ff:ff
inet 192.168.180.5/30 brd 192.168.180.7 scope global eth0
inet 91.xxx.yyy.zzz/28 scope global eth0
inet6 fe80::248:54ff:fe55:95e9/64 scope link
valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:40:f4:36:64:13 brd ff:ff:ff:ff:ff:ff
inet 10.127.255.209/30 brd 10.127.255.211 scope global eth1
inet 91.xxx.yyy.zzz/28 scope global eth1
inet6 fe80::240:f4ff:fe36:6413/64 scope link
valid_lft forever preferred_lft forever
4: eth2: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:48:54:56:ed:82 brd ff:ff:ff:ff:ff:ff
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Ой... теперь 91.xxx.yyy.zzz/28 и на eth0 и на eth1

Как на eth0 удалить 91.xxx.yyy.zzz/28 ?