Accessing applications from the Internet

As I understand your question, you have three applications installed on an application server running on an internal network and you want to access them from the Internet. There are a number of methods to do this and the underlying concern is of course security. If you are running three tiers (web cache, AS and DB), the only tier that needs to touch the Internet is the web cache. You can pass the web cache port through the firewall (7779 or whatever the OUI configured) to allow connections.

You can also place the web cache in front of the firewall and it can communicate to the middle tier OHS components...

through the firewall (encrypted if you want). For added security, many configurations place a firewall between the web cache and the middle tiers and another firewall between the middle tiers and the database (adding protection for the data).