Under dir \tomcat\bin you will find server.xml file Change the port in this section: <Connector port="8400" protocol="HTTP/1.1" connectionTimeout="20000" redirectPort="9400" />
to <Connector port="80" protocol="HTTP/1.1" connectionTimeout="20000" redirectPort="9400" /> The ip/domain name should just work if it points to your desktop/server I just tested it on my laptop and it worked fine after I turned off my default webserver that was already listening on port 80.