ping выдает непонятные сообщения

PING www.rambler.ru (AAA.BBB.CCC.DDD) from EEE.GGG.FFF.HHH : 56(84) bytes of data.
WARNING: failed to install socket filter : Protocol not available

64 bytes from head.rambler.ru (AAA.BBB.CCC.DDD): icmp_seq=1 ttl=38 time=2.175 sec 64 bytes from head.rambler.ru (AAA.BBB.CCC.DDD): icmp_seq=2 ttl=38 time=2.095 sec 64 bytes from head.rambler.ru (AAA.BBB.CCC.DDD): icmp_seq=3 ttl=38 time=1.872 sec

--- www.rambler.ru ping statistics --- 3 packets transmitted, 3 received, 0% loss, time 2017ms rtt min/avg/max/mdev = 1872.265/2047.771/2175.798/128.389 ms, pipe 3

Что значит этот WARNING?