I'm having a very similar error as this thread. http://www.howtoforge.com/forums/showthread.php?t=371 let me start out by saying the forwards work, I setup a seperate server with only a standalone mail server running to test router and network config and it worked fine. However I'd really like to use ISPconfig for everything. Here's the general email I get back after trying to use another external address to send to this machine. My forwards are setup, my domain is forwarded correctly, and firewall's do not seem to be blocking anything. I use debian 3.1/sarge. I used the perfect setup guide and followed every single step to the letter in setting my machine up from a fresh format to it running now. I am finding nothing in the documentation thus far that's helped so if anyone could shed some light that would be great.