netstat 'Ierrs' - meaning and possible causes

Matthew Seaman m.seaman at
Tue Oct 5 02:41:49 PDT 2004

On Mon, Oct 04, 2004 at 04:26:45PM -0600, Nathan Kinkade wrote:

> What possible type of errors comprise 'Ierrs'?  Here is an example of
> the output:
> Name Mtu  Network  Address    Ipkts    Ierrs   Opkts    Oerrs  Coll
> xl0  1500 <Link#1> <long mac> 92977239 5723973 95001292 0      2070292
> According to this, input errors amount to about 6% of the total input
> packets.  This number definitely exceeds the level of acceptable errors,
> but since I'm not quite sure what Ierrs signifies I'm not sure where to
> begin.  Bad hardware or media?  Are Ierrs received packets that are
> identifiable by a header, but otherwise mangled?

Yes -- this sort of error rate is almost always going to be bad
hardware, given that you're on an ethernet network.  (Things may be
different for wireless).

Since it's only affecting the receive side of one network card, it may
well be just that the network cable has been kinked or that there's a
bad spot in one of the conductors.  It can even be simply that some
RJ45 plugs aren't pushed into their sockets quite right.  Generally
that results in signals being reflected off the fault and so
interfering with themselves.  Try swapping in a new network cable --
at least it's fairly cheap if that is the case.

Other causes can be broken network card on the PC, broken port on your
switch. I should be pretty easy to diagnose by swapping cards in and
out and so forth.



Dr Matthew J Seaman MA, D.Phil.                       26 The Paddocks
                                                      Savill Way
PGP:         Marlow
Tel: +44 1628 476614                                  Bucks., SL7 1TH UK
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