I had not had issues with the r8169 module for realtek LAN nic for a long time, but with kernel 5.7, and current systemd, bang, suddenly stopped having networking enabled on wake from suspend.

Short term, of course, you can just do the classic. First find your nic IF ID:



askubuntu.com/questions/1029250/ubuntu-18-04-ethernet-disconnected-after-suspend

One of the answers is worth keeping because it's a clean native solution, not a sort of hacked on one:
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Create file: /etc/systemd/system/fix-r8169.service

with contents:



Then just execute:

and you should be set!! Systemd will now automagically unload-and-reload your module upon wake from suspend.

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I'm not getting consistent results with this, a reboot may be required, but I had this fail when suspend / wake was more than about 12 hours apart, but it worked when wake was closer to suspend.

This is however a good place to start.

Note that with these types of fixes, if the os is ever moved to different hardware, you want to remember that you made this and remove it, and also, test on different kernels.
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I had further issues, this time with igb driver for network:



Tried:



no joy, no connection, luckily because I have experienced this before I did not waste time checking if it was a hardware issue.

Ran:



and networking worked fine again.

This is I believe maybe related to systemd and suspend, but it could be kernels, network drivers, and suspend/resume, I don't know. All I know is this has happened on two systems now.

Posting this update in case anyone else out there has this issue, since this fix seems to correct it.
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