I have RouterOS x86 on the virtual machine, and Routerboard RB751U-2HnD (by default there MTU=1500)
It is necessary to me to reduce MTU on local ethernet interfaces (ether2-master-local and ether3-slave-local).
I reduce MTU and L2MTU on these interfaces (from WinBox), however actually nothing has changed.
How to fix this bug?