Best Method would be to set up the system that is to be the web server with a static IP address.
Then with Apache go in and change the httpd.conf file to reflect a port of choice such as 8077.
Now go in and set a firewall exception for Apache with port 8077
Now verify that the web server works at the local system that is hosting it
Now that it works at the local system hosting it go to another system and try to get to the web server via IP address and port such as
http://192.168.1.12:8077 where 192.168.1.12 is replaced with whatever IP address your web server is using as a static IP address. Your index.html or home web page should load.
NOTE: Nobody on the Internet will be able to see your private web server because there are no port forwarding settings configured on your router. If later you wanted to make the web server accessible from anywhere on the internet you would then have to go in and set a port forward configuration on the router as well as make sure you are using a port that is not blocked by ISP. However XAMPP is configured in such a way that it should really only be used for development offline or private network vs to be used for actual hosting of a real server on the Internet. XAMPP can be security hardened if later you want to do this, but by default its very minimum security to make it easy for developers who are not familiar with how to get it all working, able to get it working but insecure.
XAMPP is the easiest method to getting Apache working etc with Perl or PHP support etc. XAMPP will have Apache installed and you will want to edit the httpd.conf file to change the port from port 80 to like 8077. Reason for this is so that your requests to the local intranet web server connects locally to your server and doesnt try to go out on port 80 outbound to the internet.
