FlightAware Discussions

Message "Route MTU changed...."

Hi,

i am getting frequently this kind of message in the logs:

[2021-08-26 10:15 CEST] mlat-client(4417): Route MTU changed to 1492
[2021-08-26 10:16 CEST] mlat-client(4417): Route MTU changed to 1476

Anything to be worried about? Any impact? Or just normal behavior?

It’s not harmful, but it’s a bit unusual for it to flap between different values (this means that the path MTU is changing frequently) - do you have an unusual network setup?

(mlat-client uses the path MTU to decide on the maximum datagram size to use)

Hi,

define “unusual” :grinning:

I am using a router which is extended with a repeater on the upper floor. Both are operating as a mesh network using the same SSID. This is a specific option offered by the manufacturer AVM. The repeaters are integrated transparently and the clients are moving between them without disruption.

No issues at all so far, i cannot evne say by when this messages start coming in.

It’s currently on my AirSquitter, but not on my backup Raspberry.

I also checked the connection log in the router. The device itself did not switch between Router and Repeater, it is connected to the repeater all the time.
This was my first thought that it was caused by switching the connection.

Quick Update:
I removed one of the repeaters from the Mesh network and use it as dedicated extender.
So far no messages, will check it over the day