Fragmentation on UDP layer possible?

Roman Mamedov rm at
Sun Aug 12 21:06:11 CEST 2018

On Mon, 13 Aug 2018 02:53:44 +1000
StarBrilliant <coder at> wrote:

> I know Wireguard can already do IP layer fragmentation. (Just set
> tunnel MTU >= 1441 then fragmentation will be turned on)

Is that really expected to work? I tried setting MTU 9000 on both ends of a WG
tunnel, but large packets still do not seem to come through properly. Did you
try using it like that in any kind of environment (aside from that one
restrictive network)?

In theory using MTU 9000 or such would help lower the huge overhead percentage
of running IP over VXLAN over IP over WG over IP. I was looking into that the
other day, but my idea was to fragment VXLAN packets across multiple WG ones,
which turned out to be impossible (VXLAN RFC forbids fragmentation).

With respect,

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