I thought it would be as easy as editing Tomcat’s server.xml to have Tomcat bind on port 80 but that was not the case. Non root users cannot bind to low port numbers and I wouldn’t like to have my Tomcat run as root.
I resorted to iptables to redirect connections from port 8080 to port 80. It’s just easy as running two commands:
iptables -t nat -I PREROUTING -p tcp --dport 80 -j REDIRECT --to-port 8080
service iptables save
While the first one makes the redirection the second one guarantee the redirection will be there after a system reboot.
Don’t change any default Tomcat configuration to change port numbers. Run from authbind and from running your Tomcat as super user!