Steamdeck evading download from Lancache instance

[Pessimal]

As mentioned in the topic it seems my steamdeck is for some reason evading downloads from my lancache instance (https://lancache.net/)
When I go to the steamdeck desktop and ping lancache.steamcontent.com I can see the reply from my local lancache server IP as expected.
The system is working for my desktops systems but via from steamdeck I get neither HIT nor MISS in the lancache access log.

Anyone else have experience with lancache and steamdeck?

[Pessimal]

Well the way it is set up is that all devices on my Network receive the address of my pihole via DHCP as a DNS resolver the pihole then sends out the IP of my NAS (lancache) for the lancache.steampowered.com Domain.
A ping from my steamdeck shows that this works and lancache.steamcontent.com gets redirected to my NAS

Also any steam desktop instances will correctly identify the NAS as a cache instance as I can see in steams "content_log.txt" log

[2022-04-05 16:22:54] Enabling local content cache at '::ffff:c0a8:122' from lookup of lancache.steamcontent.com.
[2022-04-05 16:22:54] Adding cache type 'LANCache' on host '::ffff:c0a8:122'	

On the steamdeck however the content_log.txt doesn't contain those lines.

[Pessimal]

I had to add lancache.steamcontent.com to the /etc/hosts file on the steamdeck, I can only speculate there might be an additional dns resolver active aside from what is mentioned in /etc/resolv.conf. Could also be related to IPV6. Anyway it works for now, not a nice solution but whatever

[Pessimal]

I didn't change anything in /etc/resolv.conf, just wanted to express that as expected my pihole IP is in /etc/resolv.conf
What I did was add the lancache.steamcontent.com IP to /etc/hosts, I just checked and it has at least survived a reboot and a steam client update this morning. So for now all is good.
I will think about using lancache as my upstream for pihole in the future I just want to avoid making my NAS critical to my internet access. But anyway the deck ignores the IP it gets from the pihole and resolves lancache.steamcontent.com in some other way so I'm not sure it would change anything. As I said even without the /etzc/hosts entry a ping form the deck Konsole lands me at my NAS address as I would expect so no Idea what the steam client is doing to require the /etc/hosts entry. And yes IPV6 support is already disabled in my router though I think that only affects WAN addresses.

[Silence]

steam client updates are different from system updates ;)

[jdancouga]

I am having this trouble as well though not on steam deck but on Linux Desktop. My windows machine uses the lancache server as expected, but my Mint 21 desktop refuses to use the cache server. If I try ping "lancache.steamcontent.com" with the steam client closed, it will resolve to the cache server IP. However, when the steam client is opened, the ping resolved IP for the "lancache.steamcontent.com" no longer points to the cache server.

Originally posted by Pessimal:

I had to add lancache.steamcontent.com to the /etc/hosts file on the steamdeck, I can only speculate there might be an additional dns resolver active aside from what is mentioned in /etc/resolv.conf. Could also be related to IPV6. Anyway it works for now, not a nice solution but whatever

I can confirm this solution also applied to Linux Desktop.

[DUDA]

On what I've read; the windows steam client does a check for an existing cache at start time. This is visible in the logs. The steam client on linux seems to not do that for some reason. This is probably just a missing feature on the linux client.

The resolv.conf is a hacky workaround at best, but oh well here we are.

[Marlock]

for some reason

probably for "spaghetty code" reasons

[fmillion]

This doesn't appear to work at all anymore. Steam Deck now seems to only support downloading via HTTPS, which destroys any ability to cache:

[2023-11-19 22:52:27] Created download interface of type 'SteamCache' (7) to host cache6-ord1.steamcontent.com (cache6-ord1.steamcontent.com)
[2023-11-19 22:52:35] HTTPS (SteamCache,272) - cache7-ord1.steamcontent.com (192.168.32.31:443 / 192.168.32.31:443, host: cache7-ord1.steamcontent.com): cache7-ord1.steamcontent.com/depot/1628351/manifest/7142797467379774956/5/16168438043521755883 - received 0 (Invalid) HTTP response
[2023-11-19 22:52:35] HTTPS (SteamCache,272) - cache7-ord1.steamcontent.com (192.168.32.31:443 / 192.168.32.31:443, host: cache7-ord1.steamcontent.com): Closing connection

I blocked HTTPS traffic to my LanCache instance from the Deck and forced *.steamcontent.com to resolve to my LanCache for testing. If not disabled, downloads work but are not cached since it just uses LanCache's HTTPS forwarding.

[Marlock]

there might be a way to add your lancache's certificate to steam so that the extra hoop doesn't break chain of trust in steam's eyes?

[fmillion]

Originally posted by Marlock:

there might be a way to add your lancache's certificate to steam so that the extra hoop doesn't break chain of trust in steam's eyes?

Yeah, that's an interesting idea. I would have to rework the LanCache container a bit to actually proxy rather than just pass HTTPS connections but I might experiment.

[British Bulldog]

any updates on this? I'm also having the same issue. It works great on my Windows PC, Steam Deck ignores the cache.

There's an issue open on the github for this:
https://github.com/lancachenet/monolithic/issues/186

[un_synapse]

Windows Stem client is doing the same.

Only way to "fix" it is to modify the hosts file to point the DNS to you lancache IP. It WILL NOT respect the IP it gets from DNS anymore for some reason.

[ashb33t]

I tried modifying hosts file. hasnt worked for me

[ashb33t]

I had some luck... i was able to force steam to use the cache server by setting up a wildcard A record in pihole.

[Marlock]

nice trick! kudos! and thanks for sharing it!