My LAN consists of an Ubuntu desktop (192.168.0.100) and a Windows 7 laptop (192.168.0.101) behind a DIR-330 router (192.168.0.1), connected via wired connection. My external IP address, for purposes of discussion, is xxx.xxx.111.61 (verified on http://simplesniff.com). Apache is installed on the desktop and configured to answer on port 80. IPtables or any other firewall is not in use. I have configured the router to forward port 80 to the desktop.
When I type 192.168.0.100 into the browser address bar in either the desktop or the laptop, I correctly see the Apache "It works" page. However, when I try with the external IP address the browser just keeps "connecting", it doesn't even time out after a few minutes of waiting. I opened the DMZ to the dekstop to see if that would work, but it does not help at all. I know that the machine can receive non-localhost connections because the laptop can access it on the LAN IP address.
What might be wrong? What should I troubleshoot?
Thanks.