I know there are some tools including firejail and bindtointerface on standard Linux Distros, but they don't run in userland, so whenever the deck updates they will be overwritten.
Anyone have any ideas how to block access on a Steam Deck?
Uh, under Windows use NetLimiter. Under Linux? Try AppArmor based policies, otherwise... No idea.
Thanks for the suggestion, I think the main issue is doing it on the Steam Deck. On a native Linux machine it's easier. I don't see a way to install OpenSnitch on the Steam Deck with the read-only file system and whatnot. I think a pi-hole and block DNS might be easier than trying to mess with SteamOS.
You can't install applications on steam deck and there is a read only file system???? Whaaaatttt???????
Edit: I asked a friend that has a steam deck, he explained you can easily disable the read-only system, do whatever you want on a Linux system and reenable it afterwards.
From what i understand any changes to the system outside of the userland will be overwritten after a SteamOS update.
No you can install them persistent and update your OS