vxlan on top of wireguard

[Goran]

I have configured a distributed swith (vxlan) on top of a wireguard
tunnel. I learned it from https://insom.github.io/journal/2017/04/02/
but did not tried the workaround described there. The workaround
states that wireguard has some sort of bug and the
hardware-accelerated checksums must be disabled: ethtool -K $i tx off
. As the article is from last year, I tried it first without this
workaround. With that I could send icmp packets but no tcp.

Sometimes I could send a tcp packet with crazy MTU like 64 or so. Does
someone knows why this strange behaviour exists?

With workaround all works fine.