Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.
Dismiss

Why would I be told "no carrier" when there are green lights at both ends?

0 views
Skip to first unread message

Henry Law

unread,
Jan 17, 2019, 1:32:49 PM1/17/19
to
I have a Linux server (actually a Dell PC mini-tower) with three network
connections: one via the onboard socket and the other two via PCIe cards.

On one of the cards there is no network connectivity and "networkctl"
says "no-carrier". But there are green lights on the NIC and on the
switch port at the other end (yes I tried a different cable).

I thought a green light meant there was a carrier, i.e. that level 0 was
operating. I must be wrong, but what do the lights mean in that case?

--
Henry Law n e w s @ l a w s h o u s e . o r g
Manchester, England

Jaimie Vandenbergh

unread,
Jan 17, 2019, 2:04:09 PM1/17/19
to
On Thu, 17 Jan 2019 18:32:48 +0000, Henry Law <ne...@lawshouse.org>
wrote:

>I have a Linux server (actually a Dell PC mini-tower) with three network
>connections: one via the onboard socket and the other two via PCIe cards.
>
>On one of the cards there is no network connectivity and "networkctl"
>says "no-carrier". But there are green lights on the NIC and on the
>switch port at the other end (yes I tried a different cable).
>
>I thought a green light meant there was a carrier, i.e. that level 0 was
>operating. I must be wrong, but what do the lights mean in that case?

That's what they're supposed to mean, and usually do.

I had an Intel X540 fail on me recently that presented the same as
yours, lights up but no traffic on either port. Firmware would still try
and PXEboot, the card was recognised and driver loaded by the OS, no
carrier. Everything was working except the actual networking. Same
behaviour under CentOS and FreeBSD. Firmware update made no change.

Toss into the recyclers and pick up a new one.

Cheers - Jaimie
--
"I'd tried caffeine a few times; it made me believe I was focused and
energetic, but it turned my judgment to shit. Widespread use of
caffeine explains a lot about the twentieth century."
- "Distress", Greg Egan

Henry Law

unread,
Jan 17, 2019, 6:16:10 PM1/17/19
to
On 17/01/2019 19:04, Jaimie Vandenbergh wrote:
> Toss into the recyclers and pick up a new one.

PS you were quite right. Replaced and it's now working fine. Thank you.

Jaimie Vandenbergh

unread,
Jan 18, 2019, 6:25:37 AM1/18/19
to
On Thu, 17 Jan 2019 23:16:09 +0000, Henry Law <ne...@lawshouse.org>
wrote:

>On 17/01/2019 19:04, Jaimie Vandenbergh wrote:
>> Toss into the recyclers and pick up a new one.
>
>PS you were quite right. Replaced and it's now working fine. Thank you.

Sometimes it's the only language these bastards understand.

Cheers - Jaimie
--
I love children, especially when they cry, for then someone takes them away.
-- Nancy Mitford
0 new messages