[ILUG] dead pings

[Deim Agoston]

Hello !

A friend of mine asked me to scan a host whether he can ssh into the host
or not (he got a login but the admin said that he provides only https).
When I tried to nmap the machine to discover is it true or not I got no
responses. I know /proc/sys/net/ipv4/icmp_echo_ignore_all directive and
setting it 1 turns off all the messages but when I tried to use the -P0
option I got no responses too. How can he achieve this ? Some kind of
tricky ipchain rules ?
Thanks,
Ago