ip access-list extended e1-in
  ! Allow fragmentation needed messages (type 3 code 4)
   permit icmp any 192.168.0.0 0.0.255.255 packet-too-big
  ! Allow outbound ping and MS style traceroute (type 0)
   permit icmp any 192.168.0.0 0.0.255.255 echo-reply
  ! Uncomment to allow ping to the inside net (type 8)
  ! permit icmp any 192.168.0.0 0.0.255.255 echo
  ! Uncomment to allow traceroute
  ! permit icmp any 192.168.0.0 0.0.255.255 ttl-exceeded

URL:
Обсуждается: http://www.opennet.me/tips/info/214.shtml