Required Ports for Steam
The following are ports you need to have open on your router or firewall for Steam to operate normally.
Note: Many schools, universities, business 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/business network or a proxy.
Ports required for Steam can not be re-mapped to HTTP or reconfigured to a custom port range.
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: