Hello
I tried playing on battle net recently with three friends. We are all in the same city, ping approximately 6ms to each other, have port forwarded 6112 UDP correctly and selected the ‘prefer port 6112’ in the starcraft menu. We played a 4v4 comp stomp and the performance was terrible! Most of us are even connected to the same ISP and all of us have reasonable VDSL2 connections. I am so puzzled why it was laggy/choppy.
We had hoped to relive a bit of nostalgia during this COVID-19 period but found the whole process quite frustrating!
I can’t find any official documentation on what the game actually requires for an optimal network connection. Can someone please provide a link or confirm what router settings/firewall rules blizzard prefer to run this game optimally? Like the original, is 6112 UDP still preferred or has something changed? I have read about UPNP being used and non-Blizzard websites and forums suggest forwarding 6112-6119. Can someone please confirm what’s actually required???
In addition, is it best to fix the turn rate or select dynamic for best performance?
Many thanks
I turns out the port forwarding info is no longer publically available. But there is this post that lists all the various ports. Looking at it, do you also have TCP 6112 set up?
Good find! Although I don’t understand why it is so well hidden 
Yes sorry I do have TCP forwarded as well. Luckily TCP+UDP is the default selection on my router hah!
I switched upnp and NAT-PMP on today. Coincidentally I had a very smooth game on BGH with 5 other players. The router log shows that a random port was assigned to my computer when I logged into the battle net lobby, but then the port was removed once the game started. Perhaps it used 6112 or perhaps it was another application that made this request?!
Edit:
An update for anyone that’s interested…
I used Wireshark to log packets while playing. Even when my router states a port has been assigned using upnp Wireshark still shows my computer communicating through port 6112. Turning the 6112 port forward off or changing the setting in the options to prefer port 6112 doesn’t seem to have an effect. Does the UPNP port assignment ever actually get used? It seemed broken to me??