Post #225508
2026-02-03 00:53 UTC
@TechSupport@equestria.social MTU on all machines is set to 1500 (at least according to `ip a`), the bridge interface at the router is also set to 1500, and the PPPoE tunnel that it routes to has an MTU of 1492.
Replies (1)
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@TechSupport@equestria.social 2026-02-03 01:05
@Karcsesz hmm. Setting the mss clamp (via mangle or otherwise) makes sense at least, as it signals that return packets payload should not exceed the mss. This is normally a non-issue since most hosts will not try and send/route packets >1500 over the internet, but I guess Microsoft is opportunistically trying to optimize the connection with jumbo packets (and failing badly). If it worked, it'd make a lot of sense (4200 bytes seems suspiciously close to a quarter of a 16k disk read), but not great when it fails.