when using some stock kernel you probably should run insmod ip_alias, or modprobe it. in 2.2.x there used to be some problems with aliases, but there are no more. > ifconfig eth0:22 206.29.139.35 broadcast 206.29.139.255 netmask 255.255.255.0 > route add -host 206.29.139.35 dev eth0:22 counting maybe starts with eth0:0, but it doesen't matter. 22 is as good as first alias as :1 and :0, AFAIK