We have a white list of ports on our network, and the Steam client cannot connect to the server. Which ports do I need to open to make it work?


2 Answers 2


There's a Steam Support page on this:

Your network must be configured to allow Steam access to the following ports (in order from highest to lowest priority for QoS users):

Steam Client
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 4380

Dedicated or Listen Servers
TCP 27015 (SRCDS Rcon port)

Steamworks P2P Networking and Steam Voice Chat
UDP 3478 (Outbound)
UDP 4379 (Outbound)
UDP 4380 (Outbound)

Additional Ports for Call of Duty: Modern Warfare 2 Multiplayer
UDP 1500 (outbound)
UDP 3005 (outbound)
UDP 3101 (outbound)
UDP 28960

  • 3
    I had a nearly identical answer about ready to post when you ninja'd me. :P Nov 7, 2011 at 20:56
  • Ephemeral ports are assigned automatically by the TCP stack; none of these are ephemeral. They should all be outbound, with the possible exception of the MW2 one. Apr 22, 2014 at 16:09

This (2024) is a bit different list than the first answer (2011). From link

To log into Steam and download content:

HTTP (TCP remote port 80) and HTTPS (443)
UDP remote port 27015-27050
TCP remote port 27015-27050

Steam Client

UDP remote port 27000-27100: Game traffic
UDP local port 27031-27036: Remote Play     ( share your Steam local multi-player 
TCP local port 27036: Remote Play           games with friends over the internet, ) 
UDP remote port 4380

Dedicated or Listen Servers

TCP local port 27015 (default): SRCDS Rcon port
UDP local port 27015 (default): gameplay traffic

Steamworks P2P Networking and Steam Voice Chat

UDP remote port 3478
UDP remote port 4379
UDP remote port 4380
UDP remote ports: 27014-27030

It is a bit unclear on how to prioritize multiplayer packets without prioritizing steam downloads.

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