new steam lancache functionality!

[billthecatt]

Seeing this in the changelog for the latest steam beta client from Dec 20:

General
Support a LAN event using DNS injection on lancache.steamcontent.com to set up a local explicit caching proxy for downloads.

Any details on what this is and how we can leverage?

More details here (still pretty vague)
https://steamcommunity.com/groups/SteamClientBeta/announcements/detail/1698352047820654696

[chong601]

I have tried on my own spin of this repo (modified unbound and NGINX to support single network interface mode) and I can confirm that this method will work.

However, based on my understanding how Steam does the Lancache source thingy, existing domains that we have redirected still needs to be pointed to the Lancache server, but I believe that this repo existing configuration will work even if Steam only has one lancache.steamcontent.com entry in Unbound, provided that Steam launcher itself didn't bug out and use Steam content sources instead.

Single network interface Lancache are a bit complex because you would need to define the server_name to all of the hostnames that needed to be cached.