Question : How do I add an external DNS route to point to an interal IP

I have an external domain name that I need to point to an internal IP example:

secure.test.com

that has to resolve to an internal IP
192.168.1.100

How do I add this in DNS in server 2003 if the FQDN is different then the external domain name?

Answer : How do I add an external DNS route to point to an interal IP

That is correct you need to make sure you have the correct domain name in Forward lookup zones.

Make sure you have an A record pointing to the correct internal IP address