# Ethernet won't start automatically

## grant123

I'm rsyncing / on my system to / on an identical remote system every night.  I have it all scripted with certain exceptions built in and it works great except for one issue.  After the rsync, the remote system reboots and when it comes back up, the USB ethernet interface doesn't start automatically.  If I reboot it again after that, everything works perfectly.

Which files should I try not rsyncing to fix this?

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## Ant P.

I'm going to guess (blindly) that it depends on something hardware-specific in /etc/udev or /lib/udev that's getting wiped out and regenerated in the wrong order.

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## Hu

Sync the systems, perform your double reboot, then run the rsync again with -vn to show changes without applying them.  Examine the set of files that are scheduled for another update, which should be minimal since this is done right after a regular update.  One of the files in that list is likely relevant to your problem.

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## grant123

Many thanks for the excellent suggestions.  I may have it narrowed down to something in /var/, /root/, or /lib64/rc/ but maybe I'm speaking too soon.  The system is remote so I don't get to test as often as I'd like.  I'll report back once I have more info.

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## grant123

The culprit appears to have been /var/lib/ntp/ntp.drift.  If this file is deleted, the system in question fails to start its network interfaces on boot unless it is rebooted a second time.  Why would that happen?

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