Hello, When executing arp (on host A below), it lists 36 address pairs for an interface (eth1). This doesn''t make sense to me. The interface is NAT''ed though. There are only two NICs on my computer and only two computers in my domain: to isp | | eth1 +------------+ |host A | |(does NAT | |for host B) | +------------+ | eth0 | +-------+ |host B | +-------+ The list in arp includes google.com! Regards, David Koski david@KosmosIsland.com
(Duhh!) The question is, is it normal to have an arp cache with entries that don''t even belong in the network? If not, what needs to be done to keep them out? David On Sun, 3 Feb 2002 19:07:17 -0800 David Koski <david@kosmosisland.com> wrote:> Hello, > > When executing arp (on host A below), it lists 36 address pairs for aninterface> (eth1). This doesn''t make sense to me. The interface is NAT''ed though.There> are only two NICs on my computer and only two computers in my domain: > > to > isp > | > | eth1 > +------------+ > |host A | > |(does NAT | > |for host B) | > +------------+ > | eth0 > | > +-------+ > |host B | > +-------+ > > > The list in arp includes google.com! > > Regards, > David Koski > david@KosmosIsland.com > _______________________________________________ > LARTC mailing list / LARTC@mailman.ds9a.nl > http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://ds9a.nl/lartc/
On Sun, Feb 03, 2002 at 07:52:12PM -0800, David Koski wrote:> (Duhh!) The question is, is it normal to have an arp cache with entries that > don''t even belong in the network? If not, what needs to be done to keep them > out?This happens if you don''t have a default gateway and something in the network is feeding you proxy arps, telling you ''yes, I can reach google.com''. Add a default route on A to B and the problem will disappear. Regards, bert -- http://www.PowerDNS.com Versatile DNS Software & Services http://www.tk the dot in .tk Netherlabs BV / Rent-a-Nerd.nl - Nerd Available - Linux Advanced Routing & Traffic Control: http://ds9a.nl/lartc
On Mon, Feb 04, 2002 at 11:02:32AM +0100, bert hubert wrote:> On Sun, Feb 03, 2002 at 07:52:12PM -0800, David Koski wrote: > > (Duhh!) The question is, is it normal to have an arp cache with entries that > > don''t even belong in the network? If not, what needs to be done to keep them > > out? > > This happens if you don''t have a default gateway and something in the > network is feeding you proxy arps, telling you ''yes, I can reach > google.com''. > > Add a default route on A to B and the problem will disappear.Eh, he means: add a default route from your router (A) to your internet router (which I am missing in your picture). -- <ard@telegraafnet.nl> Telegraaf Elektronische Media http://wwwijzer.nl http://leerquoten.monster.org/ http://www.faqs.org/rfcs/rfc1855.html Let your government know you value your freedom. Sign the petition: http://petition.eurolinux.org/
On Mon, 4 Feb 2002 11:02:32 +0100 bert hubert <ahu@ds9a.nl> wrote:> On Sun, Feb 03, 2002 at 07:52:12PM -0800, David Koski wrote: > > (Duhh!) The question is, is it normal to have an arp cache with entries that > > don''t even belong in the network? If not, what needs to be done to keepthem> > out? > > This happens if you don''t have a default gateway and something in the > network is feeding you proxy arps, telling you ''yes, I can reach > google.com''. > > Add a default route on A to B and the problem will disappear.I had a default route but no gateway as you said! Once I did: route add default gw 1.2.3.4 eth1 The problem went away. And it makes sense. Thanks! David Koski david@KosmosIsland.com