I had the same problem upgrading from kernel 2.0.x to 2.2.13: SIOCADDRT: Invalid argument
I solved the SIOCADDRT error message updating the /etc/init.d/network script. Just to be safe I installed also the netbase_3.12-2 package for Slink (http://www.debian.org/~rcw/2.2/warnings.html). BTW, just to be pedantic, the loopback interface is supposed to be on a class A network, so the netmask should be 255.0.0.0 and the command is: ifconfig lo 127.0.0.1 route add -net 127.0.0.0 netmask 255.0.0.0 lo I wonder if kernel 2.2.x does not require loopback setted properly anymore... Niccolo Firenze - Italy -- Contro la Tariffa Urbana a Tempo - http://www.notut.org