Running Tomcat on port 80 as non-root
Nat intranet to internet:iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE
Map port:iptables -t nat -A PREROUTING -p tcp --dport 80 -i eth0 -j REDIRECT --to-port 8080
http://www.linux.org.mt/article/tomcat-ports