[CentOS] Ethernet poor performance

NiftyClusters Mitch niftycluster at niftyegg.com
Wed Jul 2 19:29:53 UTC 2008

Good list:
Also add multiple runs of "traceroute" and also try ping,  ping -f ,
ping -A and ping -R.  See also ping6
If routes are dynamic we have one answer to the problem, I would
expect traceroute to have 'one' answer on a simple net.
If packets are falling on the floor then we need to know why.

The different invocations of ping can tell you if packets drop at slow
or fast transfer rates.
ping -R is slightly different than traceroute but if the return routes
flip one way then the
other we should know why.

Watch out for /etc/sysconfig/network-scripts/ifcfg* where hardware addresses,
subnet masks, device driver links/ names etc. no longer match the hardware
when things move.

Consider snooping packets on the link to see if all is as you expect.  I keep an
old, slow  network hub (not a switching hub) for the times when I want
to see the bits on the wire and
not the bits that the local driver is able to show me.

On Wed, Jul 2, 2008 at 8:55 AM, nate <centos at linuxpowered.net> wrote:
> Robert Moskowitz wrote:
> > Any Idea where I should look to fix this?
> - What version of CentOS?
> - What type of network card?
> - What driver is it using?
> - What type of device is on the other end of the network card?(Switch, hub,
>  router etc)
> - Can you verify that the speed and duplex settings match on both ends of
>  the connection?
> - I assume the ping you are running is only 1 or 2(if there's a hub/switch
>  in between) hops away?
> - Any errors reported by ifconfig ? any collisions?
> - Try replacing the card itself? maybe it is bad.
> nate
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> http://lists.centos.org/mailman/listinfo/centos

T o m M i t c h e l l

More information about the CentOS mailing list