Many university networks and proxies block required ports for Steam operation - please consult your network administrator to ensure the required ports are open if you are using a university network or a proxy. Ports required for Steam can not be re-mapped to HTTP or reconfigured to a custom port range.

Advanced

For generic Steam HTTP/HTTPS requests, your proxy should allow the following domains:

steampowered.com

steamcommunity.com

steamgames.com

steamusercontent.com

steamcontent.com

steamstatic.com

akamaihd.net

Most of the non-web traffic is usually UDP but can be TCP as well. For that, the IPs will all be from the Valve network (AS32590), and a list of those IP blocks can be found here: