No networking before login?

Ferdinand · 2022-05-18 07:34:55

I'm using Network Manager exclusively for my networking; internal DHCP client, and configuring it with nm-connection-editor.

I'm in the mood to disable all networking until I log in. Primarily for security purposes, but also because I simply don't need any networking when I'm not logged in, so everything can just sit on it until I'm good and ready

The problem is I got a bit confused trying to figure it out, and would like to appeal for some insight.

I want to connect automatically when I log in, so I want my nm-connection-editor settings to hold (i.e. I want the settings in /etc/NetworkManager/system-connections to be as I have defined them).
I see two ways about it:

Changing Network Manager configuration
Changing systemd configuration

With respect to the first, I tried adding

[main]
no-auto-default=*

to /etc/NetworkManager/NetworkManager.conf (it's the only content in the file), but that turned out to be futile of course, as the automatic connections, defined in /etc/NetworkManager/system-connections, kicks in, and connects the interfaces I have defined.

Now, that other avenue would be to delay networking until after I logged in - but to my understanding I can only hold a systemd service until a specific target, and there is no target for "the first interactive login" - so am I'm basically looking at disabling the system service and creating a user service for starting Netwok Manager? That would have to be per user, as, in principle, I can't know which user logs in first. And I'm not sure what that would mean for other services waiting for networking - will networking started with a user service fulfil "network.target"?

I could just try of course, but I figured this maybe is interesting for others too, and is complicated enough to warrant a request for insight, rather than just resorting to semi-ignorant hit-and-miss'ing?

dogknowsnx · 2022-05-18 09:35:44

This could be achieved by setting up e.g. gnome-keyring

Ferdinand · 2022-05-18 16:12:21

Thank you for replying, @dogknowsnx!

I'm afraid I need a little spoonfeeding on that one... for example, how would I configure, or use, gnome-keyring to prevent my computer from connecting to a wired network until after I log in?

Oh, but you woke my brain cell - with reference to my list above, there should be a third way - to disable all network interfaces on boot, and then enable what I need on login?

tucuxi · 2022-05-18 17:26:40

I probably have not understood all nuances of your endeavor. Starting NetworkManager as a user instead of a system service seems too obvious.

dogknowsnx · 2022-05-18 19:48:27

Since you mentioned security, encrypting the network password came to mind, where it wouldn't be stored by NM in clear text, thus requiring NM (or any other app - for that matter) to "go through the keyring" on login. Here's another spoonful...

EDIT: You will still have to find out yourself whether/how this applies to wired networks, though...

Last edited by dogknowsnx (2022-05-18 20:01:54)

seth · 2022-05-18 21:00:58

Is this a wired connection?
=> Explicitly configure the connection profile for the nic, set autoconnection to false and then up it w/ your session.
https://access.redhat.com/documentation … networking

Arch Linux

#1 2022-05-18 07:34:55

No networking before login?

#2 2022-05-18 09:35:44

Re: No networking before login?

#3 2022-05-18 16:12:21

Re: No networking before login?

#4 2022-05-18 17:26:40

Re: No networking before login?

#5 2022-05-18 19:48:27

Re: No networking before login?

#6 2022-05-18 21:00:58

Re: No networking before login?

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