MX - Path MTU under 1500 and AutoVPN

[Raphael_L]

Hi ,

Does anyone have a path MTU lower than 1500 on their WAN and using AutoVPN ? ( Eg : GRE tunnels )

How is the MX handling that ? I know for a fact that if you configure PPPoE on the MX , it lowers the MTU to 1492. I'm just curious about other scenarios.

Will the MX notice that the path MTU is lower than 1500 ? Will it magicly lower it's MTU ?

I'm aware that you can call support to lower the MTU. I'm wondering what kind of setup / issues you guys have encountered.

Cheers ,

[whistleblower14]

MX = 17.10.2

MG = 1.11

[Ruud Hochstenbach]

Note that the MG21 is having issues (some firmware near future should fix this though)..

MTU size is default 1280 on a MG21.

Call support for a patch they can run. So the MG21 will start to use MTU1500.