Virtual Server can not be found by others

[5381!]

Hi there,

I'm running WinXPSP2. I already installed and configured a ts server by the latest ts2_server_rc2_202319.exe.
I'm also using NO-IP due to DNS matters (arcanum.servegame.com).
The server is online for about 1 1/2hrs, but it's only me that can Login and no one else.
A friend of mine tried to join the server several times without success. He pinged the address (as above). No response anyway.
I forewarded the standartport (8767) in my router (FRITZ!Box) and even deactivated my firewall. I simply have no more clues.

Why is it only me that can join the server and nobody else?

In case I left out any important information please let me know because that problem is a pain in my neck and I want it to be solved quickly!

Greetz

5381!

[BHKai]

If you have dsl, your modem might also act as a router.