Yes, I rebooted after changing mtu_fix. 2, 3, 4 times
But now I’m focusing at the following fact …
Same WireGuard Provider :
An own WireGuardServer with 1000 MBit/s U/D)
Same Internet provider, same router
WireGuard on my smartphone / Android (= Linux) … FullSpeed: ~25 MBit/s
WireGuard on my AR750S-756 / Linux … FullSpeed: ~ 2 MBit/s
Both are linux-based, so the OS is “similar” …
My smartphone is rooted and I disabled IPv6 on it! = FullSpeed: ~25 MBit/s
My AR750S-756 has IPv6 enabled = FullSpeed: ~ 2 MBit/s
I tested both devices ( smartphone / AR750S-756 ) at the some uplink / router and this one hast “DS-Lite”, so it’s connecting through IPv6 and tunneling IPv4 ( if I understood correctly).
But if there is an IPv4-Only device, it works of course, because of that IPv6/IPv4 tunneling.
Fact: My smartphone is now an IPv4-Only device, because I disabled IPv6 on it.
Question / Suggestion : If I would config the AR750S-756 like my smartphone, then it should work with WireGuard perfectly.
But how / What to do?
Other possibility : I’m using WireGuard for Android v0.0.20181218 an there it works.
So maybe the reason for low speed is an old WireGuard version. I think I read about WireGuard Beta an the GL-INET firmware.