LanCache Explained: Speed Up Repeat Game Downloads and Windows Updates on Your LAN

LanCache is a local cache for your network. The first time a device downloads a game, patch or update, the data comes over your internet connection at normal speed and counts against any data cap. When a second, third or tenth device asks for the same content, the cache on your own network can serve it instead. At that point your LAN, cache server and storage set the speed, and your ISP is no longer involved.

Bashir lists five places where this pays off: Steam, other PC game launchers, consoles, Windows updates in offices, and LAN parties. Here is how each one holds up against the project's own documentation, and where Windows admins should be careful.

How LanCache works: a cache plus a DNS redirect​

LanCache's documentation says you need two services. One is a depot cache (the "monolithic" container). The other is a special DNS service. The cache passes content requests through to Steam, Origin and other services when it doesn't already have the files, and serves them locally when it does. The DNS service answers most queries normally. When a query is for a supported caching service, it points the client at the cache instead.

The project treats DNS as the part that makes or breaks the setup:

• The quickstart runs on a modern Linux distribution with Docker. You clone the project's docker-compose repository, edit the .env file and run docker compose up -d.
• The main .env settings are LANCACHE_IP (the address DNS hands out for the cache), CACHE_ROOT (where cached data is stored, ideally on a separate volume from the OS) and CACHE_DISK_SIZE.
• Your router must hand out only lancache-dns to clients. Any other DNS servers belong in the UPSTREAM_DNS option.

The project's common-issues page puts it bluntly: "The most common cache issue we see is incorrectly configured DNS." If a client has two DNS servers, it "will use them both and bypass the cache for about half of the requests." On recent Linux hosts there is another trap. systemd-resolved listens on port 53, so you have to disable its stub listener before the cache host can bind DNS to all addresses.

Section summary: LanCache redirects DNS for known download hostnames to a box on your network. If DNS is set up wrong, much of the traffic skips the cache.

Task 1: Steam games and updates​

Steam is the classic use case, and it appears by name in the community-maintained uklans/cache-domains list that LanCache uses. Bashir says his 100Mbps fiber line gets about 10–11MB/s, while repeat downloads from LanCache "can easily hit 90MB/s."

Those numbers are plausible. 100Mbps works out to 12.5MB/s at most, and 90MB/s is about 720Mbps, which fits a decent gigabit LAN. Still, this is one person's result, not a benchmark. Your speed depends on the cache server's disk, its network interface and whether the content is already cached. If the cache sits on a slow hard drive in an old NAS, it will not deliver gigabit speeds.

Bashir also docks his Steam Deck so it pulls updates from the cache over wired Ethernet. That's a good tip for handheld owners.

Task 2: Epic, Riot, EA and Battle.net​

Bashir says downloads from Epic Games, the Riot Client, the EA app and Battle.net are shared across his PCs almost immediately. The domain list mostly supports this. It has entries for Epic Games, Riot Games and Blizzard/Battle.net, plus Ubisoft, Rockstar, Call of Duty and others.

Epic Games has an interesting history here. LanCache's FAQ says that as of 2019-05-30, Epic Games moved its CDN servers and launcher to HTTP for content delivery, which made its downloads cacheable.

EA is less certain. The list has an "Origin" entry flagged as mixed content, with a note that it should be enabled for HTTP only or with an HTTPS proxy, "else origin client download fails." That doesn't prove the current EA app is fully covered. A LanCache GitHub issue from 2021 reported Origin struggling unless a "safe downloads" option was re-enabled. If EA titles don't seem to be caching, check this first.

Task 3: Consoles​

Bashir says he tested PlayStation and Xbox Series consoles and calls the results flawless. The domain list backs up the idea: it includes Sony/PSN, Xbox Live and Nintendo. His example is Battlefield 6, where a patch under 10GB on PC can reach about 50GB on Xbox. In a home with several consoles, each one downloads that patch separately.

One benefit is that console owners don't have to configure the consoles themselves. An industrial IT guide makes the same point, noting that LanCache's DNS-based approach requires no endpoint configuration, which suits mixed fleets that include gaming consoles. The consoles just need to receive the right DNS server from the router.

The catch is that only hostnames on the list can be cached, and services change their CDN setups over time. A console download that uses an unlisted or HTTPS-only host will go straight to the internet as usual.

Task 4: Windows updates in the office​

This is the part most relevant to WindowsForum readers, and it has solid support. The domain list has a "wsus" entry described as "CDN for Windows Updates." Its host file covers *.windowsupdate.com, *.update.microsoft.com, *.dl.delivery.mp.microsoft.com and *.do.dsp.mp.microsoft.com, among others. It also lists officecdn.microsoft.com, so Microsoft 365 Office content can be cached too, not just OS patches.

LanCache's FAQ calls DNS interception "the easiest way to achieve the caching of services like Windows Update, without modifying people's computers." Bashir recommends it for Windows offices with 10 to 20 PCs, especially bandwidth-sensitive ones such as call centers and video editing shops, where a morning of simultaneous updates can clog the connection.

There is real evidence that this kind of caching works at scale. A separate project, nginx_lancache, which caches Windows Update and other services for schools, reports that over 12 months on a network of 13,500 users across 33 links, it saved 160.55 terabytes, averaging 13.38 terabytes per month, with an average efficiency ratio of 3.58:1. That's a different project in a different environment, but it shows the approach can deliver results.

Where admins should pump the brakes​

Windows Update caching is also where LanCache has caused the most trouble:

• Downloads can break. In a 2021 LanCache issue, one user reported that Windows 10 and 11 devices could see available updates but could not download the content, and the only fix found was bypassing the cache entirely.
• "We couldn't connect to the update service." A 2019 issue reported this error even though DNS resolved correctly. The user's workaround was starting the DNS container with DISABLE_WSUS=true.
• The same switch works for other services. The DNS container supports DISABLE_${SERVICE}=true flags, so you can turn off any single service that misbehaves and keep caching the others.

Microsoft also has its own built-in options. Windows includes Delivery Optimization for peer sharing, and Microsoft documents BranchCache for WSUS and Configuration Manager setups. There's an important caveat, though: BranchCache isn't supported for content downloaded using Delivery Optimization in Windows 11. If your organization already manages updates through WSUS, Configuration Manager, Intune or Connected Cache, LanCache is an extra layer to evaluate carefully, not a replacement. Test it on a few machines before pointing the whole office at it.

Section summary: LanCache can cache Windows Update and Office CDN traffic. Treat it as useful but fragile, and keep DISABLE_WSUS=true in mind as a fallback.

Task 5: LAN parties​

LAN parties are the project's home turf. The LanCache DNS documentation says its solution is designed to support anything from a couple of people at home, to thousands of people at gaming events. The cache-domains FAQ describes its audience as anything from 10 people in a friend's garage to thousands at an exhibition center.

Bashir says setup for his LAN parties used to take nearly half a day. Now he lets LanCache pull the fully patched games once, and everyone installs from the cache while the pizza arrives. The one thing to plan for is the first download: the cache can't serve a game it hasn't fetched yet, so the smart move is to download the big titles through it a day before the event.

What LanCache can't do​

Bashir says plainly that LanCache "isn't magic," and the project agrees:

• HTTPS is off-limits. The FAQ explains that the SNI proxy listens on port 443 and just passes through any HTTPS traffic. It is unable to inspect the traffic, or cache it. That's why Netflix, YouTube and normal browsing won't speed up.
• The first download is normal speed. A cache only helps after it has the content.
• One device gets no benefit. Bashir notes that a single PC or console gains nothing, because nothing on the network asks for the same content twice.
• Storage matters. The maintainers warn that content rarely downloaded more than once wastes cache space and can push out more useful files. The quickstart says the cache tries to keep about 10GB free, controlled by MIN_DISK_FREE.
• Disk speed can be the bottleneck. For heavy workloads, the industrial guide says use NVMe SSDs or high-IOPS SAN, since sequential read performance matters more than IOPS for bulk downloads.

Is the "tenfold" claim fair?​

Partly. The number describes the gap between Bashir's internet speed and his LAN speed, not a boost to his internet connection. If your connection is already gigabit, the gap is much smaller.

His real motivation is more convincing. He set up LanCache because his ISP's Fair Usage Policy kept catching him. With three PCs, two PS5s and two Xboxes, every big patch counts seven times against his limit. With a cache, it counts once. His claim that you "use no ISP bandwidth" only applies to repeat downloads of cached content, but for households with data caps, that's the main benefit.

Want to try it? Start small. Use a spare Linux box or VM with a dedicated SSD volume, set lancache-dns as the only DNS server your router hands out, enable Steam first, and add Windows Update last, once you know how to switch it off.