lkml.org 
[lkml]   [2004]   [Oct]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Neighbour table overflow.
You may also be the 'victim' of a poorly configured router.

Out-of-the box, Cisco routers come with proxy ARP enabled;
they will reply to ARP requests for any IP they can route,
that isn't routed via the interface they receive an ARP
request on. This makes them more 'plug-and-playful' for
equipment that talks IP, but doesn't understand routing
(assuming any still exists).

Check the output of
arp -an
and see if there isn't a single MAC accounting for the lion's
share of your ARP cache. If there is, seek and destroy^H^H^H^H^Hfang


On Wed, Oct 27, 2004 at 02:30:32AM +0200, Dominik Karall wrote
> --nextPart2038980.5ceDjSAWoH
> Content-Type: text/plain;
> charset=3D"iso-8859-1"
> Content-Transfer-Encoding: quoted-printable
> Content-Disposition: inline
>
> On Wednesday 27 October 2004 01:06, David S. Miller wrote:
> > On Wed, 27 Oct 2004 00:11:26 +0200
> >
> > Dominik Karall <dominik.karall@gmx.net> wrote:
> > > On Tuesday 26 October 2004 23:52, Ernst Herzberg wrote:
> > > > On Tuesday 26 October 2004 19:39, Dominik Karall wrote:
> > > > > can anybody explain why i get thousands of "Neighbour table
> > > > > overflow." messages? i didn't get such ones with older kernels
> > > > > (~2.6.6).
> > > >
> > > > Do you set a default gateway?
> > >
> > > yes, default gateway is set to our server.
> >
> > Do you use a large subnet mask? For example /16 or /8 or
> > something like that?
> >
> > If so, you will need to bump up the neighbour table garbage
> > collection thresholds under /proc/sys/net/ipv4/neight/default/
> > Specifically gc_thresh1, gc_thresh2, and gc_thresh3
> >
> > You probably have a huge number of machines on your subnet.
>
> the subnet mask is set to 255.255.0.0, and there are machines from 172.16=
> .0=3D
> =3D2E1=3D20
> to 172.16.1.254. but not all ips are reserved. there are "only" about 100=
> =3D20
> machines in the network.
> i will try to change the values of gc_thresh*, maybe it helps. thx!
>
> dominik
>
> --nextPart2038980.5ceDjSAWoH
> Content-Type: application/pgp-signature
>
> -----BEGIN PGP SIGNATURE-----
> Version: GnuPG v1.2.5 (GNU/Linux)
>
> iQCVAwUAQX7sKgvcoSHvsHMnAQJXqgP/eFTl/SzsI83Q/WgZmlaJ9xPCXsSxFbQm
> 2UmR4cHDZti6mOzKeAOI/O91S+xTkFvdYmVgm+k+TAaUpy6OHa1Lx84y9H7uMa7P
> 7afLf9+qQ00pi+uUp9srhihpiwt1yEYRWuvc9NaZhYfl9EJdeQmGNy6M7tlSwV07
> mxTCNjVqBBU=3D
> =3DZ8MD
> -----END PGP SIGNATURE-----
>
> --nextPart2038980.5ceDjSAWoH--
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" i=
> n
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>
>
> --__--__--

--
Voice: +61 8 8202 9040
Email: jpearson@sa.pracom.com.au

Pracom Ltd
288 Glen Osmond Road
Fullarton, South Australia 5063

Ph: + 61 8 82029000
Fax: +61 8 82029001

CAUTION: This email and any attachments may contain information that is
confidential and subject to copyright. If you are not the
intended recipient, you must not read, use, disseminate, distribute or
copy this email or any attachments. If you have received this
email in error, please notify the sender immediately by reply email and
erase this email and any attachments.

DISCLAIMER: Pracom uses virus-scanning technology but accepts no
responsibility for loss or damage arising from the use of the
information transmitted by this email including damage from virus.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 14:07    [W:2.216 / U:0.012 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site