don't remember which post exactly, you edited someones elses answer.
server was listening on port 2000
client was trying to connect on port 2000
I could see via wireshark that there was some normal stuff going on via TCP (no NACKS, resets or whatsoever), but no screen appeared
yes firewall was fully disabled on the server side and I even disabled to firewall on the client side.
no that gave the same result
No I didn't bother posting it on the main site. It just didn't work between my two personal laptops, but worked immediately when I tried to connect to a PC "on the field"