Multiple Network connections (eg fo Internet and Mesa/Ethercat)

That is crazy.

The CPU alone is worth than 3 times the car I drive.

Well back on topic. It appears this has been solved for ethercat by removing the settings in /etc/network/interfaces and disabling the network that is connected to the ethercat slaves. As soon as the intercace is enabled, we loose internet connection. Ethercat is mapped at the MAC address level so it must bypass the Linux networking stack. I guess this make sense given that Ethercat uses its own protocol to maximise performance.

I'll worry about setting it up for a Mesa card another day (when I'm ready to play with one).

There still should be a way to force Linux to go out on a specific NIC so if there are ideas, let me know.

tommylight wrote:

It is that easy.
 

Yeh, never had an issue with mesa cards (or ethercat for that matter). IN fact you can set up ethercat and swap to a mesa card on the same NIC without any dramas.

nobody yet has helped with the original problem which is specifying  which NIC should be used for the default network/internet connection....

Tommy, I'm not ignoring anything. The PC is at work and its a public holiday today. Like you, I assumed this would be simple and used exactly your methods. Whether the fixed IP for Mesa is set up in the  GUI or  the intferfaces file makes no difference. Using the config file lets you set the coalescing for Intel NICs which you can't do in the GUI. This surprised me as its worked with Bookworm before.

I don't want to have this running all the time. I just wanted to work with hardware at my office desk from time to time whether its mesa or ethercat.

I think ethercat is different to a Mesa config because it does not use an IP address or interfere with other network TCP/IP comms. I have not tested but I think ethercat slaves can coexist with normal network hardware (eg. On the normal network). The only way I can get it to work is to disable the ethercat NIC in the GUI.

So yes, its a routing issue and its a long time since I've played with static routes but i've never done it with Linux. I thought it would be easy.