GMod Server stuck on LAN.

So I tried hosting a dedicated server today using steamcmd and the batch file to start it. I port-forwarded the following ports both for TCP and UDP: 27005-27015 and added them as an exception in Windows Firewall. But whatever I do, no one can connect to my server. I even have the server.cfg done already, everything according to a video where it worked at the end. That’s my router btw:

FRITZ!Box Fon WLAN 7570 vDSL

Strange thing is, portforward.com doesn’t list it, so I really don’t know what’s going on… Any ideas how to fix this and bring it to the internet list?

sv_lan 0
heartbeat
change map
Try that

sv_lan 0 is already set in the server.cfg, also tried the other 2 options. No effect, not even with connect ip command. It has a ping that changes but it’s not on the internet list. Also, no one can join me because it says the server is not responding.

Maybe someone who also has a dedicated server on windows 7 can explain me his exact way to do it?
Oh and one sidenote I forgot about my router. I cannot portforward from 27015 to 27015 like it is shown in many videos and guides. The numbers have to be different to work.

Its a port range, do 27000 to 27050 or from 27005 to 27025.

The port HAS to be open.

Start up the server, and test the ports you’re using on here:

what exactly does heartbeat do?

I’ve ran my servers with it off, and there was no difference between it being off or being on

Strange… Tested 27000, 27050, 27049, 27048 -> Timed-Out.
But 27015 is open. I also edited the port numbers in router config and firewall to 27000-27050 for TCP and UDP.