Insists on defaulting to non-standard mtu 2312

[romanrm]

Hello,

I find that the interface is created with MTU 2312 by default. This is very surprising, because the rest of the WiFi infrastructure is typically not ready for this, and the WiFi AP or router uses the regular MTU 1500 on its interfaces. As such, in my case I could not connect to the rtl8812au machine from my LAN, which uses MTU 9000 (because there were invisible 1500-MTU "bottlenecks" in the middle, and TCP-negotiated highest-common-mtu packets of 2312 were being cut off or dropped).

Moreover, even using Debian's standard /etc/network/interfaces "mtu" clause in the wlan0 section does not affect the resulting MTU of the upped interface. Only using "post-up ifconfig $IFACE mtu 1500" fixed it.

I suggest that the regular default of MTU 1500 is used instead, with the possiility left for the user to raise MTU if required.

[MarkusTieger]

I agree with that said above