Свежая система debian sid:

localhost:/# ping localhost
PING localhost (127.0.0.1) 56(84) bytes of data.
^C
--- localhost ping statistics ---
3 packets transmitted, 0 received, 100% packet loss, time 2014ms

localhost:/# ping ya.ru
PING ya.ru (213.180.204.8) 56(84) bytes of data.
64 bytes from ya.ru (213.180.204.8): icmp_seq=1 ttl=55 time=27.0 ms

localhost:/# ip rule show
0: from all lookup local
32766: from all lookup main
32767: from all lookup default

Что забыл разрешить?