If you want to have 2 servers share one IP,you may consider to use apache web server to dispatch requrest to internal web servers.
case 1
router --> port forward 80 --> pc1
--> port forward 81 --. pc2
case 2
router--> port forward 80 --> PC1 apache --> pc1 tomcat
--> pc2 tomcat
case 1
router --> port forward 80 --> pc1
--> port forward 81 --. pc2
case 2
router--> port forward 80 --> PC1 apache --> pc1 tomcat
--> pc2 tomcat
選擇“Disable on www.wenxuecity.com”
選擇“don't run on pages on this domain”
