Networking is going down on some of our machines. This is happening very randomly. Restarting networking is fixing the issue. I found the following in the kernel logs:

Mar 19 18:19:05 <host> kernel: [4854950.244533] ADDRCONF(NETDEV_UP): eth1: link is not ready
Mar 19 18:19:05 <host> kernel: [4854950.465902] ixgbe: eth1 NIC Link is Up 10 Gbps, Flow Control: None
Mar 19 18:19:05 <host> kernel: [4854950.466895] ADDRCONF(NETDEV_CHANGE): eth1: link becomes ready
Mar 19 18:19:16 <host> kernel: [4854960.725876] eth1: no IPv6 routers present

We have 10g card installed on these servers. (Intel Corporation 82599EB 10-Gigabit SFI/SFP+).

OS: Debian 6.0
Kernel: 2.6.32-5-amd64
ixgbe version: 3.18.7

Can someone help me with this ?

1 Answer 1


There are three possible error sources:

  • Peer (Other Server or Switch)
  • Cable
  • Yout NIC / Server

To find the cause, I would:

  • monitor your interface with mii-tool -l eth1
  • at the same time the peer (swich or other server)

If only one of them reports the link flapping, then it is likely that the the machine/ switch on which the flapping is reported is defect.

If both report the link flapping:

  • Replace the cable
  • Replace either server/ switch

...and see when the issue is gone.

  • Thanks for your reply. mii-tool seems to be deprecated on the server. But one strange thing happened. When I tried doing ethtool -t eth1, the same issue is reoccurring. So I think we can rule out the problem with Peer or cable
    – Vaisakh
    Mar 19, 2014 at 18:32
  • Yea I know but most distros ship mii-tool so I though I use this :) So you see the problem on both sides?
    – vanthome
    Mar 19, 2014 at 19:13
  • The other side is a switch.
    – Vaisakh
    Mar 20, 2014 at 7:08
  • The strange thing which I noticed is the default route is getting disappeared when the issue is happening.
    – Vaisakh
    Mar 21, 2014 at 18:57
  • Well that's normal if the network is managed by tools like NetworkManager. They tend to automagically tear up and down things on link-up and link-down events.
    – vanthome
    Mar 21, 2014 at 23:41

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