Change MTU Size of Windows TAP-Adapter

[abdufa]

Dear Community,

I am having issues running a snap on the VirtualCore. The snap runs just fine on a native Linux system but when installed on the VirtualCore, connection issues occurs. The error is linked to the MTU size of the network card. On a native linux system the MTU size is changed easily but I do not know how to accomplish this on a (Virtual)Core. 

In Windows I do have access to the settings of the TAP-Adapter of VirtualCore but I cannot go higher than MTU = 1500. I need at least 3000.

I would appreciate any help to solve this issue.

Kind regards

abdufa

[FooFighter]

Hello,

the setting of our TAP-Win32 adapters MTU defaults to "1500" which is the required setting for ethernet bridging.

For standard use cases this should work. You can find further infos about tap-adapter configurations here:

https://openvpn.net/community-resources/reference-manual-for-openvpn-2-4/#tun-tap-driver-setup

As a workaround of your problem you can try to run a virtual control with port forewarding (advanced setting) this may solve your problem.

Regards,

Oliver

[abdufa]

Hello,

thank you for the reply. I tried your suggested solution to use port forwarding in the advanced settings section. This comes with more issues because after activating port forwarding the installed snap cannot connect to other devices in the network even if you add the necessary ports to the settings.

Is there any way to increase the size of MTU of the TAP-Adapter?

Regards

abdufa

[FooFighter]

Hello,

I am sorry, but I do not know a solution how to change the MTU size of a TAP-Adapter. This software is used as it is for our use-case.

But do you have checked the posibility with port-forewarding?

From the virtual ctrlX the Windows host PC has the IP address 10.0.2.2.

Maybe you can install a proxy on your pc (px.exe for example) then you need to adjust the fireawall inside the virtual control to use proxy enabled and direct to the px proxy (10.0.2.2:3128).

Regards, Oliver

[abdufa]

Hello,

thank you for your anwer and apologies for the delayed reply! I tried using port forwarding but it came with more issues regarding which ports to forward (which we do not know exactly). Another solution we found was to use a more powerful host pc. That reduced the connections drops.

The question now is: how to run the snap on the realtime cores on the ctrlx so that there are no performance issues? If I install the snap on the ctrlx, it runs on the non-realtime core. 

Regards

[CodeShepherd · Accepted solution]

Same questions was posted to this topic. Please have a look there.

In short you have to write a celix bundle to be able to run deterministic with the system.