Had this problem a while ago. Inside the LAN i could access HTTP/FTP, however, outside the LAN i wasn't able to (external connections). Solved it by reformatting. After reformatting, I installed things 1 by 1. Apache2, PHP, MySQL, they all worked (LAN and external). This proved my Port forwarding and everything was working fine. Today I went to reformat my main computer, and installed Samba on my server so I could easily transfer files. However, after installing samba and adding ports 137-139 TCP/UDP to my list of open ports (Fedora Core 2 Security Config), I could access everything from the LAN, but not externally (same symptoms as before). Nothing else had changed except the installation of Samba...

Anyone ever heard of this problem? Or perhaps know a fix? (im reformatting right now, gunna skip samba this time =P)