Another question from a new linux user!

Not sure exactly how to phrase this but here goes. I have set up an Apache server along with a MySQL data base. I am using perl to generate some dynamic web pages. I want to access the pages from both the Web as well as a LAN that the server is on. The server is the only Linux box on the LAN. I have both static HTML pages as well as the dynamic pages. The router I have does not support loopback NATing.

If I use the same webpages for both local and Web access they do not work properly because of the links. (ie if I provide a local link they do not work for the web and vice versa). I guess I could create two different pages to basically do the same function but this does not seem to be the correct solution, just a work around.

My question: What is the proper way to resolve this? Is this a job for DNS? Is there a way in Perl to check for an outside IP address and return the link correctly? If this is the way to go I will dynamically create all of the web pages. Any suggestions would be helpful. Thanks.