CS:GO and QoS

[haunch]

CS:GO traffic is occurring on a UDP port other than what's listed in the official knowledge base. In two matchmaking games, I saw traffic for UDP ports 27025 and 27041, but the range for 'game client traffic' is listed as 27000-27015.

Is there a more up-to-date document or resource which describes the current port scheme used by CS:GO?

From the official knowledge base document [1]:

"
UDP 27000 to 27015 inclusive (Game client traffic)
UDP 27015 to 27030 inclusive (Typically Matchmaking and HLTV)
TCP 27014 to 27050 inclusive (Steam downloads)
UDP 27031 and 27036 (incoming, for In-Home Streaming)
TCP 27036 and 27037 (incoming, for In-Home Streaming)
UDP 4380
"

[1] https://support.steampowered.com/kb_article.php?ref=8571-GLVN-8711

[Falro the Great]

Seems normal given that 27025 falls within the Matchmaking range, which CS:GO uses, and 27041 falls within Steam downloads, which is normal for textures and the like.

[haunch]

27041 is listed as a TCP port for Steam downloads, but my game was taking place on it (which is not a Steam download and does not use TCP). Also, I just played a matchmaking game which used port 27061, which falls outside all listed ranges.

Additionally, when starting matchmaking, a flurry of UDP requests is sent out to multiple IP addresses with the destination ports ranging from 27015 to 27062. So, I'm guessing that the knowledge base article which describes the port ranges is out of date.

[Falro the Great]

Ah, I see now, I failed to notice the "TCP".

It may be out of date, yes. You could try to contact Steam Support for clarification.

https://support.steampowered.com