iptables -A INPUT -p icmp –icmp-type 8 -j ACCEPT
iptables -A INPUT -p icmp –icmp-type 30 -j ACCEPT

ICMP type 8 is “echo-request”, which you may substitute for ’8′ if you wish.
ICMP type 30 is “traceroute”, which, again, you may substitute for ’30′ if you wish.

Ahh i read the above from a forum and lost the url in the process. Pity. Acknowledgments to the person who wrote this short but useful item.