xx.xx.xx.xx (real ip)
xx.xx.xx.xx (real ip) via proxy server
What is the explanation for this? Not using port 80 if that makes any difference.
It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, see the FAQ.
Your NAT does not support NAT hairpinning (a.k.a. NAT reflection, NAT loopback, etc.). Enable NAT hairpinning if you can, or get a better NAT that does hairpinning.
Here's the IETF's (the Internet standards body's) "Best Current Practices" documents on how NATs are supposed to behave in this situation:
I'm guessing you're talking about the IP Address listed at http://www.whatismyip.com/ That is your external IP Address and you won't be able to access your Apache web server until you forward port 80 in your firewall settings on your router.
You can find documentation on how to forward your port here
That's quite normal; I'd bet you are trying within a LAN. If so, you can either use your local address (