Server unaccessable after unplugging and plugging in ethernet cable

[Rexl]

Hi,

 

First of all thanks for taking the time reading my post. I have a bit of a issue with my server , it isn't that big of an issue but more an inconvenience. When ever I unplug the ethernet cable from my server whiles it is running and replug it the server remains not accessable and I have to restart the entire server before I can access it again via the web UI. Running a ping command from another computer will give me the message that the server is unaccessable aswell, which would let me indicate that the entire link is down not just the webui.

 

Mar 31 15:36:44 Ark kernel: r8169 0000:07:00.0 eth0: Link is Down
Mar 31 15:36:44 Ark kernel: br0: port 1(eth0) entered disabled state
Mar 31 15:38:26 Ark init: Switching to runlevel: 0
Mar 31 15:38:26 Ark init: Trying to re-exec init
Mar 31 15:38:27 Ark nginx: 2022/03/31 15:38:27 [alert] 8090#8090: *346899 open socket #25 left in connection 6
Mar 31 15:38:27 Ark nginx: 2022/03/31 15:38:27 [alert] 8090#8090: *346474 open socket #21 left in connection 10
Mar 31 15:38:27 Ark nginx: 2022/03/31 15:38:27 [alert] 8090#8090: *346477 open socket #20 left in connection 13
Mar 31 15:38:27 Ark nginx: 2022/03/31 15:38:27 [alert] 8090#8090: aborting
Mar 31 15:38:28 Ark kernel: mdcmd (37): nocheck cancel
Mar 31 15:38:29 Ark emhttpd: Spinning up all drives...
<.. server continues to shutdown from here..>

 

As you can see the link goes down when I unplug the cable but it doesn't go back up when the cable is reseated (in this case I left it unplugged for 10-20sec before reseating it) and stays down, the lights on the port do start to blink as if it would indicate that is active. I suspect it has something to do with the 2nd line in the log, that is that the eth0 is entering disabled state.  I only have one ethernet port on the server, which is the one on the motherboard (ASUS Prime B450M-A which uses a RealTec RTL8111/8168/8411 chip)

 

Hope someone can help me out with this one.

Thanks in advance.

ark-diagnostics-20220331-1623.zip

[Squid]

Not sure about the problem, but why are you unplugging the cable (on a seemingly semi-regular basis)?

[Rexl]

5 minutes ago, Squid said:

Not sure about the problem, but why are you unplugging the cable (on a seemingly semi-regular basis)?

 

I first noticed it once i was tieding up closet where the switch and modem/router are located, as i was just moving the switch around an unplugging everything and repositing everything I noticed that I couldnt connect anymore after i was all done and thought it might have been the switch that i was using (was an old HP switch), but as I bought a new switch i was curious if the problem still persisted which it did. So today i just tested it again to be 100% sure the problem was still there before I posted this.

 

Not planning on doing it that frequently anymore but in the case that i need to do it again, its kinda annouying that i have to power down the entire server for switching around ethernet ports on the switch for example.

Edited March 31, 2022 by Rexl

[Frank1940]

One problem that can occur if everything is not connected to an earth ground is that you can get a potential voltage difference between (say) the switch and (say) the server.  The current surge which might occur in this situation could lock up the electronics on one or both ends when you plug it while under power.  In the worst case scenario, the surge just destroys the chips involved. 

 

Many of the cheaper consumer-grade switches have no provision for an earth ground so you can't even set things up properly.  In the pro-consumer arena, There may be a grounding screw provided for that devices that use wall-wort power supplies.    The user then has to actually use the screw to connect a grounding wire to a suitable earth ground.

 

This doesn't even consider when in low-humidity conditions, the user can accumulate a static charge and then discharge that charge into a network cable connector or cable port on the device.  (Always grab an earth ground-- or use a static wrist band-- before grabbing a cable or getting near any port on a device!)  

Edited March 31, 2022 by Frank1940

[Rexl]

Thank you for the reply Frank,

 

I am kinda ruling out any grounding issues, as all the outlets are grounded and even the switch is grounded via the power supply. Furthermore I did a test where I just unplugged the switch from the outlet (not even touching the case of the switch, just the powercord) and even than the server isn't reachable after the switch started up again.

[Rexl]

Anyone got any idea perhaps?

[Frank1940]

Swap out the cable.

 

If that does not work, you should next try a Network card to replace on onboard NIC.  (You should probably turn off the onboard NIC in the BIOS..)  It is generally recommended that you use an Intel card as they are very high quality.

[Rexl]

Thanks again Frank! Was hoping on a setting within UnRaid or somewhere. But will definitely try those steps