eth2 LINK DOWN / LINK UP Spam in SystemLog

[Xruptor]

I'm not entirely sure why. But after setting up a RT-AC86U for my sister, she is getting this spam notice in her system log constantly. I cannot figure out what it is or what port is causing it.

Aug 19 11:39:01 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link DOWN.
Aug 19 11:39:04 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link UP 1000 mbps full duplex
Aug 19 11:39:20 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link DOWN.
Aug 19 11:39:23 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link UP 10 mbps full duplex
Aug 19 11:40:01 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link DOWN.
Aug 19 11:40:04 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link UP 1000 mbps full duplex
Aug 19 11:40:21 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link DOWN.
Aug 19 11:40:24 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link UP 10 mbps full duplex
Aug 19 11:41:02 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link DOWN.
Aug 19 11:41:05 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link UP 1000 mbps full duplex
Aug 19 11:41:40 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link DOWN.
Aug 19 11:41:43 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link UP 10 mbps full duplex
Aug 19 11:41:48 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link DOWN.
Aug 19 11:41:51 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link UP 1000 mbps full duplex
Aug 19 11:41:53 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link DOWN.
Aug 19 11:41:56 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link UP 1000 mbps full duplex
Aug 19 11:41:59 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link DOWN.
Aug 19 11:42:02 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link UP 10 mbps full duplex
Aug 19 11:42:07 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link DOWN.
Aug 19 11:42:10 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link UP 1000 mbps full duplex
Aug 19 11:42:13 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link DOWN.
Aug 19 11:42:15 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link UP 1000 mbps full duplex
Aug 19 11:42:17 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link DOWN.
Aug 19 11:42:21 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link UP 10 mbps full duplex
Aug 19 11:42:31 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link DOWN.
Aug 19 11:42:34 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link UP 1000 mbps full duplex
Aug 19 11:42:40 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link DOWN.
Aug 19 11:42:43 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link UP 1000 mbps full duplex
Aug 19 11:42:45 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link DOWN.
Aug 19 11:42:48 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link UP 10 mbps full duplex
Aug 19 11:43:02 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link DOWN.
Aug 19 11:43:05 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link UP 1000 mbps full duplex
Aug 19 11:44:18 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link DOWN.
Aug 19 11:44:21 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link UP 10 mbps full duplex
Aug 19 11:48:15 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link DOWN.
Aug 19 11:48:18 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link UP 1000 mbps full duplex
Aug 19 11:48:27 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link DOWN.
Aug 19 11:48:30 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link UP 10 mbps full duplex

Aug 19 12:08:54 kernel: eth3 (Ext switch port: 2) (Logical Port: 10) Link DOWN.
Aug 19 12:09:03 kernel: eth3 (Ext switch port: 2) (Logical Port: 10) Link UP 1000 mbps full duplex
Aug 19 12:09:14 kernel: eth3 (Ext switch port: 2) (Logical Port: 10) Link DOWN.
Aug 19 12:09:17 kernel: eth3 (Ext switch port: 2) (Logical Port: 10) Link UP 1000 mbps full duplex
Aug 19 12:09:18 kernel: eth3 (Ext switch port: 2) (Logical Port: 10) Link DOWN.
Aug 19 12:09:21 kernel: eth3 (Ext switch port: 2) (Logical Port: 10) Link UP 1000 mbps full duplex

Can anyone tell me what this is? How can I fix it? Also what port is it targeting? As far as I know all the ports are reading as 1GB yet this seems to keep happening in the system log. If there is no way to track this down, is there a way to disable this message? Everything seems to be working fine with no disconnects or anything but this message keeps popping up.

 

[Grisu]

I would say you have an ethernet problem, but everytime only few (~3) seconds maybe you dont realize it.

 

[Xruptor]

I would say you have a ethernet problem, but everytime only few (~3) seconds maybe you dont realize it.

Yeah but I'm trying to track it down and don't understand where this is coming from. What port or anything. The spam is pretty bad and like I said it's not really affecting the connection at all. I'm just hoping someone here has some insight on how to fix this or at least disable it.

 

[john9527]

I'm just hoping someone here has some insight on how to fix this or at least disable it.

Old fashioned debugging....unplug each ethernet cable hooked to the router one at time until it stops to see what device it is.
It looks like it's having trouble negotiating the connect speed...

 

[ColinTaylor]

@Xruptor What John said . If I had to make a guess I'd say it might be a device that's gone into sleep/standby mode.

 

[sfx2000]

Can anyone tell me what this is? How can I fix it? Also what port is it targeting? As far as I know all the ports are reading as 1GB yet this seems to keep happening in the system log. If there is no way to track this down, is there a way to disable this message? Everything seems to be working fine with no disconnects or anything but this message keeps popping up.

Maybe a bad cable or a bad ethernet card in the device that is attached to that port.

 

[Xruptor]

Maybe a bad cable or a bad ethernet card in the device that is attached to that port.

It turned out it was one specific ethernet cable that kept doing it. But I literally had to pull out and test every single cable one at a time. I wish the error would at least tell you what port it was. Since the port number it suggested wasn't even the one that was affected.

 

[Xruptor]

Update: So I had replaced all the cables thinking that fixed the problem. When I last visited I saw that the router was flooded once again with the messages. They were all brand new cables so I knew it couldn't be the cable. The little I've been able to gather seems that the eth/port from the systemlog is as follows:

Port 1 -> eth4
Port 2 -> eth3
Port 3 -> eth2
Port 4  -> eth1

Port EWAN -> eth0

Did a little research and apparently this is a very common issue. Has to do with auto negotiation or some such.
https://forums.whirlpool.net.au/archive/2006625
https://superuser.com/questions/740972/ethernet-link-going-up-down-repeatedly
https://www.snbforums.com/threads/rt-ac86u-multiple-link-down-errors.47579/
https://www.snbforums.com/threads/rt-ac86u-configure-ethernet.48550/

etc.. etc..

In putty SSH to the router. You can do the following commands.

This will tell you the current media type for the eth port
-------------------------------------
ethctl eth4 media-type

This will tell eth4 to be 1000FD
-------------------------------------
ethctl eth4 media-type 1000FD

I've tried setting the 1000FD manually but the issue still pops up. Apparently if you set it to 100FD it turns off auto-negotiate, but I don't want them running at 100FD. There has to be a way to fix this or at least prune the systemlog of this stuff. It's crazy how much spam it's getting and like I said I know the cables are fine. All the devices support 1000GFD. They all have Cat6 cables. The only thing I can think of is that one of them or more than one is hibernating and is flooded the systemlog with this message. Any ideas?

 

[Grisu]

I would say a port is dying or cables are too long or running parallel to a noisy cable.
And look inside the ports, are all pins parrallel up and clean?
Maybe a little switch between this ethernet ports could help.
Even may be a bad e-cap or power supply.

 

[john9527]

Maybe a little switch between this ethernet ports could help.

I'd definitely give this a try.....an 8-port Gb unmanaged switch is inexpensive to try and has other advantages as well.

 

[GHammer]

I have that logged each time my PC is shutdown and restarts.
If you have anything that powers down its Ethernet port (power saver, etc) or puts itself in a low power state, that is how it looks on the router.
If you have this no matter the cable or port, this would be what I'd assume and ignore the logs because it is not an error.

 

[Xruptor]

I have that logged each time my PC is shutdown and restarts.
If you have anything that powers down its Ethernet port (power saver, etc) or puts itself in a low power state, that is how it looks on the router.
If you have this no matter the cable or port, this would be what I'd assume and ignore the logs because it is not an error.

I've been trying to figure it out. It just a huge spam on the logs though. Happens every couple of seconds. I'm beginning to suspect it's the XBOX that is put on a low power state (standby). I'm looking at the other hardware but that one in particular seems to be causing the log entry more than most. The weird thing is like I said these log entries don't seem to affect performance but still gets spammed willy-nilly in it. If only there was a way to disable it or at least prune it off the logs. I'm still investigating the cause but each time I have to freaking drive to her house lol.

 

[Xruptor]

Hmm seems the spam seems to be coming from Eth2 port where the xbox of theirs is connected.

ep  2 10:41:23 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link DOWN.
Sep  2 10:42:17 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link UP 1000 mbps full duplex
Sep  2 10:42:23 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link DOWN.
Sep  2 10:43:17 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link UP 1000 mbps full duplex
Sep  2 10:43:33 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link DOWN.
Sep  2 10:44:17 kernel: eth2 (Ext switch port: 1) (Logical Port: 9) Link UP 1000 mbps full duplex

It has to be that the standby is triggering it. They don't have any other machines that I know of that are on standby and or hibernate. I think their PS4 is set to be fully off not on standby. Which is why I haven't seen it. If this is triggered by a standby or hibernate machine, that's just really annoying log spam then. I wish there was a way to disable it.

 

[Xruptor]

Well I gave up trying to figure it out or trying to turn it off.

I use the following to just get rid of it in the systemlog every hour.

sed -i.bak '/Ext switch port/d' syslog.log

it removes the lines and makes a backup just in case

 

[Xruptor]

Okay so after several months. I've managed to pinpoint it to the "Instant On" mode of the XBOX One. It triggers the LINK UP and LINK DOWN messages constantly as it's alternating between 10mbps and 100mbps while it checks for data during "Instant On". The moment the system gets turned on it goes into full 1Gbps mode. When you put it back into "Instant On" mode it goes back to the same spam in the logs. BTW I've replaced all cables with fresh cables and good ones too. This problem still persists even with direction connections with no devices to cause static and brand new cables.

I wish there was a way to disable this or at least filter these messages out automatically. It creates a lot of spam! Even with the script that I have that deletes it every hour the log is filled with it until it gets cleared. Maybe something can be implemented to filter these out before they hit the log?

Here is a thread with someone having the same issue with their XBOX.
https://answers.microsoft.com/en-us...antly-up/39893c13-d4a3-48bc-9f5f-5213aab39a04

and another one
https://answers.microsoft.com/en-us...d-router/bd32f35e-d9f0-4123-90da-b5e68abb1878

yet another one
https://answers.microsoft.com/en-us...nnection/4c346516-b14e-49d9-8f76-24e9f247e2e8

if anyone has any suggestions, please let me know.

 

[Jack Yaz]

I'd definitely give this a try.....an 8-port Gb unmanaged switch is inexpensive to try and has other advantages as well.

if anyone has any suggestions, please let me know.

A cheap switch between the Xbox One and the router will prevent the messages, as the Xbox will be spamming the switch instead ;-)

 

[Xruptor]

A cheap switch between the Xbox One and the router will prevent the messages, as the Xbox will be spamming the switch instead ;-)

Well I suppose that's one way to do it. But it does seem sort of a half-measure approach to fixing the issue. Some sort of filtering option for the system logs or an option to turn off link logging would be nice. I'll see if I have a spare switch/hub around to try out at her house.

 

[hervon]

I adapted this script found on the forums. It effectively cleans the "switch" lines in the logs according to a cron frequency of your choice (mine is every 30 mins)

#!/bin/sh
sed -i '/switch/d' /tmp/syslog.log
# sed -i '/upnpd/d' /tmp/syslog.log # not useful for you
# sed -i '/[Complete]/d' /tmp/syslog.log # not useful for you

# Add in service start :
# cru a logclean "0,30 * * * * sh /jffs/scripts/logclean"

 

[ColinTaylor]

@hervon He's already doing that. See post #14.

 

[Xruptor]

A cheap switch between the Xbox One and the router will prevent the messages, as the Xbox will be spamming the switch instead ;-)

This seems to have worked for now. Though it does seem like a cheap way to fix the issue. I'll monitor the logs and see if it triggers it anymore over the course of time. Thanks for the suggestion.