Complete list of network blocks an IPs to whitelist for steam access

[kveroneau]

This is my very first post on the steam community pages, although I have been a long term steam user. This is a very highly technical post, so I apologize beforehand as what I am attempting to do is not usual, but might be in the interest of the greater steam community.

So, firstly my ultimate goal here is to allow my internal Windows machines, which I only use for gaming purposes to only connect out to Valve's steam servers, and nothing more. Yes, I know this means that Windows cannot update itself, nor can it's telemetry services watch what I do. However, I don't think those services matter for a computer which can only speak to steam, a normally trusted Internet service.

For the longest time my Windows gaming machines couldn't talk to the Internet at all, but since Steam doesn't entirely work offline, and their offline support isn't the best at times, I thought that having my Linux router only whitelist valve's servers will be perfect to allow me to still access steam services. Today I went to the BGP(Border Gateway Protocol) page for Valve, https://bgp.he.net/AS32590#_prefixes so that I can grab every single network block I need to whitelist in order to access steam services. And it worked! Windows cannot access anything, but steam now. If anyone is curious on how to pull something like this off, I will create a proper guide at one point.

Now, for the only problems which I am seeing. So, although I whitelisted 56 network blocks, it seems that Valve uses some third party services to host the friends list and the website stuff. After it did successfully log me into my Steam account, my friends list did not load citing network connection issues, and the normal news page which displays sales and announcements also did not load into the web frame. I suspect that everything else works though. So, I am here to hopefully get an official response from Valve on which IPs or network blocks I need to whitelist in order to access my friends list and the website news and announcements pages from the Steam app.

For those interested on performing a similar feat, which I might add decreases the total Windows CPU usage during idle times to under 5%, thus has the potential to further increase gaming performance as Windows services cannot talk to Microsoft all the time and uploads will never auto-download without knowledge. I will update this post in the future with a proper guide. The device I purchased to use as a Linux router/gateway/firewall is this device from UpSystems, which has 2 1Gbps Ethernet ports, and I use an external Gigabit switch: https://up-shop.org/home/179-up-squared-gatewaypentium-n4200-w8g-memory64g-emmc-boardwovesa-plate.html

The box itself is on back-order currently, but creating a custom device with dual gigabit ethernet ports shouldn't be too difficult for modern PC builders. Such a device can either be used to control a whole in-home network, or you can use it a bridge between your gaming rig and your normal Internet router to block any traffic you deem unworthy. A business should be created behind this idea in selling "Steam restricted gateways" which will allow only steam access, but disallow all other network traffic to keep a system as pristine as possible. Gamers shouldn't need to also wear a system admin hat when their PCs have viral infections or a broken update is sent down the pipe.

[kveroneau]

So, downloading games works perfectly, as long as they are in my account already. I have create two YouTube videos to show how it looks from the Windows PC side of things, which also shows the downloading of a Steam game, and another video showing the Linux router configuration stuff. I will create an official guide for those interested.

Windows PC side of things showing the Steam client working: https://www.youtube.com/watch?v=TpmqPk9LowE

Video showing the Linux router portion of the stuff, for those curious on how I pulled it off: https://www.youtube.com/watch?v=CvGy9kIZewU

Please note, that this of course is not supported behaviour by Valve Corporation, and additional IPs will need to be whitelisted for most online multiplayer games. In the current state I have, I need to perform the actual purchase on a PC with full Internet access, or use a HTTPS proxy server on Windows to perform the purchase through the steam website. Once purchased on your Steam account, you should be-able to download and install the games onto the highly restricted Windows gaming PC.