Red Hat Bugzilla – Bug 2896
removing eth cable kills networking until cold boot
Last modified: 2015-01-07 18:37:22 EST
I was changing out the ethernet cable on a running 6.0
machine (upgraded from 5.2) and when the new cable was in
(very fast switch), I had no traffic across eth0. ifconfig
looked fine and was up. Lights on the nic and the hub, no
traffic lights. ifconfiged eth0 down and up, no go. Did a
'reboot' and it still was not passing traffic across the
port. Did a 'shutdown -h now', then brought it up and was
fine and passing traffic again.
This sounds like a hardware problem.
Some (poorly designed, IMHO) cards do this. It is almost certainly a
hardware issue. Possible workaround: rmmod followed by insmod.
Generally, forcing the driver to reinitialize the card will solve
this, but there are some *really* bad cards out there.
The chipset issue is usually something like:
- cable removed
- chipset detects no ethernet carrier; automatically tries to
renegotiate 10/100/HD/FD/whatever/TP/coax/ whatever it does;
- fails to find an ethernet connection; locks into some default mode
that may not be supported. Default mode is often 10b2 or 10b5 (coax
and AUI, respectively) -- but most cards don't have these physical