Bring USB net0 back up after power outage

grant123 · Veteran Joined: 23 Mar 2005 Posts: 1106

net0 is plugged into a powered USB hub and after the power goes out I have to manually restart the interface to reconnect. Is there a way to handle this automatically?

szatox · Advocate Joined: 27 Aug 2013 Posts: 3637

There are ways to do that, some more hackinsh than others. How is your network configured, and in what state is it after power returns?
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grant123 · Veteran Joined: 23 Mar 2005 Posts: 1106

Ok nevermind in that case. I was hoping there was something slick for this like a directive in net.conf or a udev rule.

szatox · Advocate Joined: 27 Aug 2013 Posts: 3637

Nobody said there isn't.
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grant123 · Veteran Joined: 23 Mar 2005 Posts: 1106

When power returns the net0 USB interface is down but /etc/init.d/net.net0 restart brings everything back online.

szatox · Advocate Joined: 27 Aug 2013 Posts: 3637

Ok, so you're using netifrc.
It's been a while since I played with this, and honestly don't remember how it worked exactly, but there is rc_hotplug variable in /etc/rc.conf. Give it a shot.
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grant123 · Veteran Joined: 23 Mar 2005 Posts: 1106

hotplug doesn't seem to work in this case and it must be because if the USB hub loses and regains power, net0 disappears from ifconfig but '/etc/init.d/net.net0 status' still reports 'started'.
'/etc/init.d/net.net0 restart' makes it work again. Maybe hotplug is designed to work only in the case of 'stopped' and wouldn't work in my scenario?

szatox · Advocate Joined: 27 Aug 2013 Posts: 3637

I think your net.net0 should not be explicitly enabled for hotplug to work. AFAIR it is an alternative reason to activate a device, alongside with "needed" and "manual", and if it's explicitly enabled, it won't be able to deactivate.
Probably. It is still possible that it only responds to NO-CARRIER flag or LOWER_UP/LOWER_DOWN or whatever indicates wire's status.

As an alternative: depending on the complexity of your setup, you might be able to replace it with dhclient or dhcpcd. At least one of them has morphed into a simple connectivity manager. There is NetworkManager too, it can handle devices appearing and going away.
Netifrc is still the best when it comes to the more tricky setups though.
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grant123 · Veteran Joined: 23 Mar 2005 Posts: 1106

I tried removing net.net0 from the default runlevel and enabling it in rc_hotplug but unplugging/replugging the device causes it to disappear from ifconfig and /etc/init.d/net.net0 still reports "started". Am I doing this right?

NeddySeagoon · Posted: Fri May 09, 2025 6:32 pm Post subject:

grant123,

Is plugdev any use?
It brings the interface up/down depending on the state of the wire. I don't know how well it plays with USB though.

Really hacky is to restart eth.net0 in local. I assume the system reboots and not hibernates for a power outage?
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NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

grant123 · Veteran Joined: 23 Mar 2005 Posts: 1106

I can't find much about plugdev except that there's a group with that name. Can you point me in the right direction?

NeddySeagoon · Posted: Fri May 09, 2025 7:36 pm Post subject:

grant123,

I think I had another senior moment. I was thinking of one of the following ... probably ifplugd as I get the plug bit right :)