Arch Linux

DarioP

Member

From: Geneva

Registered: 2011-01-05

Posts: 165

Choose network device per application

Hello, I am running Gnome with network-manager.
I have two network interfaces, both providing internet access, and I would like to attach Firefox to a specific one.

I went as far as learning network namespaces. So my attempt is:

$ sudo ip netns add myns                 # create namespace myns
$ sudo ip link set dev mydev netns myns  # attach mydev to myns
$ ip netns exec myns /usr/bin/firefox    # run firefox inside myns

However the second command fails with:

$ sudo ip link set dev mydev netns myns
RTNETLINK answers: Invalid argument

and I could not find any other hint to progress.
I am open to completely different solutions, but no GUIs please.

koffeinfriedhof

Member

Registered: 2017-11-30

Posts: 91

Re: Choose network device per application

Did you replace mydev with your adapter? E.g.

ip link set dev enp0s25 netns whatever

? After adding to your namespace, ip a should not list this device anymore. What is the output of ip -n myns a?

DarioP

Member

From: Geneva

Registered: 2011-01-05

Posts: 165

Re: Choose network device per application

I discovered that I can add to the namespace my (unplugged) ethernet interface, but I get the above error with the wireless interface.
Stopping NetworkManager.service and bringing the wireless interface down does not help.

ip -n myns a shows the loopback interface and the ethernet one, the wireless never shows up as

ip link set dev wlp4s0 netns myns

always results in:

RTNETLINK answers: Invalid argument

koffeinfriedhof

Member

Registered: 2017-11-30

Posts: 91

Re: Choose network device per application

For wireless you must use iw with the phy. See How to move wireless connection to other network namespace? for an example usage.

DarioP

Member

From: Geneva

Registered: 2011-01-05

Posts: 165

Re: Choose network device per application

Thanks a lot for pointing me in the right direction!
I haven't tried yet but that should work properly, although I may also setup a bridge.