I have tried a Dedicated Server utility.
The game is running on PC #1 and the server is running on PC #2.
Same subnet (192.168.192/24) and same provider, two different PCs.
When I`m trying to find my server in the server list - it is not there.
In case I switch PC #1 (with the game) to another provider (usb 3G though the cell phone) the server appears in the list.

Is it a bug or how to fix this?