Look at This: Contemporary Brochures, Catalogues and Documents

The simplest possible solution is to just uncheck that configuration option in mIRC and let iptables do the work. This means, that you should tell mIRC specifically that it is not behind a firewall. Appendix C. ICMP types This is a complete listing of all ICMP types. Note the reference pointing to the RFC or person who introduced the type and code. For a complete and absolute up to date listing of all ICMP types and codes, look at the icmp-parameters document at Internet Assigned Numbers Authority. Note Iptables and netfilter uses ICMP type 255 internally since it is not reserved for any real usage, and most likely will never have any real usage. If you set a rule to match iptables -A INPUT -p icmp --icmp-type 255 -j DROP, this will DROP all ICMP packets. It is in other words used to match all ICMP types. Table C-1. ICMP types TYPE CODE Description Query Error Reference 0 0 Echo Reply x В  RFC792 3 0 Network Unreachable В  x RFC792 3 1 Host Unreachable В  x RFC792 3 2 Protocol Unreachable В  x RFC792 3 3 Port Unreachable В  x RFC792 3 4 Fragmentation needed but no frag ...»