Re: Blocked incoming ICMP, getting outgoing ICMP [3] Destination Unreachable



Doesn't [3] need an incoming ICMP to provoke it?

ICMP, TCP and UDP can all elicit ICMP type 3 responses.

Actually, I suppose any IP protocol could elicit an ICMP type 3.

http://www.iana.org/assignments/protocol-numbers
.