WireGuard Windows should have default MTU of 1280.

Michael Tokarev mjt at tls.msk.ru
Mon Feb 21 18:53:26 UTC 2022

19.02.2022 04:23, Rujbin wrote:
> Hello,
> i am just confused. When i use default MTU the Performance on Windows is VERY poor. It is almost unuseable. It happens on multiple Windows devices. I started using MTU 1280 for a while, but why is it only Windows with that issue? First, the speed is limited to 100mbps maximum. Thats weird, when i use MTU 1280 i have 1gbps. https://i.imgur.com/ELGOWDQ.png

In our case with default MTU (of 1420 iirc), in-tunnel performance is near
the direct pefrormance. When lowering MTU to 1280, the speed reduces a bit
but not much (I guess due to larger overhead due to smaller packet size).

> This bug exists for a long time to me. I ran Wireguard on almost every provider, (i didnt check if it happens on Azure) but this bug exists on Hetzner, DigitalOcean, OVH. This is not normal. I am running the latest stable version of Wireguard Windows. Kernel module on servers and BoringTun.

I don't see a bug here.


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