It seems that docker lowers the MTU on a network interface by itself with 50 less then set on the network you connect.
- If the network has an MTU of 1500, eth0 becomes 1450.
- If you set it on 1450 (because your underlying network is encapsulated) eth0 gets an MTU of 1400
Why does this happen ? Is it because Docker encapsulates it’s own networks ?