Ethernet link going down and then up after 3 seconds.

dafyre

@pete-s said in Ethernet link going down and then up after 3 seconds.:

I have a server that shows the ethernet link going down and then up again. It is always around 3 seconds. In the log the first time it happened was 2 months ago. There are a total of 85 down/ups since then.

What could be the cause for this? Could it be another device on the LAN? Why always 3 seconds?

Excerpt from dmesg:
[28468259.557902] igb: eth0 NIC Link is Down
[28468262.617576] igb: eth0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX
[28468268.462849] igb: eth0 NIC Link is Down
[28468271.522498] igb: eth0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX
[28468274.480760] igb: eth0 NIC Link is Down
[28468277.452435] igb: eth0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX
[28468281.006518] igb: eth0 NIC Link is Down
[28468283.958191] igb: eth0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX
[28470067.093744] igb: eth0 NIC Link is Down
[28470070.033392] igb: eth0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX

Does this happen every 3 seconds all day every day, or is it random?

1337

@dafyre Random in bursts. 85 times total in the last two months.

momurda

What services are on this?
What does the switch it is connected to tell you?

matteo nunziati

any L2 managed switch with spanning tree?

1337

@momurda said in Ethernet link going down and then up after 3 seconds.:

What services are on this?
What does the switch it is connected to tell you?

It's a file server. No disruption in service has been noticed.

The switch is one of the HP procurve smart-switches. Can't remember what model but it's gigabit. I don't know what kind of logging it has, if any.

matteo nunziati

@pete-s said in Ethernet link going down and then up after 3 seconds.:

@momurda said in Ethernet link going down and then up after 3 seconds.:

What services are on this?
What does the switch it is connected to tell you?

It's a file server. No disruption in service has been noticed.

The switch is one of the HP procurve smart-switches. Can't remember what model but it's gigabit. I don't know what kind of logging it has, if any.

In my experience spanning tree on managed switches can cause random "holes". If it is a procurve 2xxx or higher it should have a console with a log command. A handy one able to filter warnings and so.
Would be interesting to log into the switch and check the file server port.

Mike Davis

Like @matteo-nunziati says, see if STP is turned on on your ProCurve. If it detects a MAC on two interfaces, it will shut one down. Then it doesn't see it, so it turns it back on. I had issues at one time with a Wireless controller (Nortel) that had proxy arp on that would cause a segment of the network (the switch the wireless AP was on) to get shutdown when a laptop would boot up.

dafyre

log in to the switch.... and then

sho log -r

That will show you the most recent entries in the log. Look for anything related to STP.

1337

I will have a look at the switch when I get on site. What you're saying makes a lot of sense.

matteo nunziati

@dafyre said in Ethernet link going down and then up after 3 seconds.:

log in to the switch.... and then
sho log -r
That will show you the most recent entries in the log. Look for anything related to STP.

I think it is:

log -r -w

Without the 'show'. The -w switch helps filtering out less relevant stuff.

Unsolved Ethernet link going down and then up after 3 seconds.