How do I determine if my router is causing a Steam connection issue? How do I configure my router to work with Steam?
Steam does not support gameplay on machines operating in a network DMZ. You must remove your machine from the DMZ in order to play through Steam.
Router issues will generally be encountered upon your initial installation of Steam, or in the event that the router's settings or firmware have been changed.
To determine if your router is the sole cause of an issue, please remove it completely from your network, connect your computer directly to the internet connection, and re-test your Steam connection.
If you are using a wireless connection to access Steam, you may encounter intermittent connection issues related to low signal strength - it is recommended that plug your machine directly into your router to ensure the highest level of connectivity.
There are several routers and versions of router firmware which are not compatible with Steam - please see the Router and Router Firmware Issues topic for a list.
In addition to the list linked above, Dual WAN routers are not compatible with Steam.
To determine if your router may be causing issues with connectivity, please observe the following troubleshooting steps:
If you are able to connect to Steam after bypassing your router, it is highly recommended that you reconfigure your router to work with Steam.
Stateful inspection or dynamic packet filtering may cause issues with Steam. If you have identified the router as the cause of your issue, disable these services.
If you do not have the original instruction manual for working with your router, please check your router for the manufacturer or brand name and the router's model number. You will need to run a search for your router manufacturer's website to find instructions for configuring your router to work with Steam.
PortForward.com is also a useful resource for router-specific instructions (please note that the information provided at PortForward.com may not reflect recent additions to the required ports for Steam).
All required ports to run the Steam application are listed here. It is possible that other games available on Steam will require further ports to be available.
Please see the Troubleshooting Network Connectivity topic for further network troubleshooting instructions.