Re: [LARTC] shared_media

["Marco Berizzi" <pupilla@hotmail.com>]

Hi Varun,

Thanks a lot for the reply. That's what I was looking for.

----- Original Message ----- 
From: "Varun Varma" <varun@mindsw.com>
To: "Marco Berizzi" <pupilla@hotmail.com>
Cc: <lartc@mailman.ds9a.nl>
Sent: Monday, May 12, 2003 1:10 PM
Subject: Re: [LARTC] shared_media


> Dear Marco,
>
> Linux, in the 2.4 kernels, has this default behaviour. The ARP reply
for
> an IP goes from any interface on the system, not just the one on which
> the IP is configured.
>
> You can change this behaviour by setting:
>
> /proc/sys/net/ipv4/conf/all/arp_filter = 1
>
> Or, if you want to control this for just one interface:
>
> /proc/sys/net/ipv4/conf/interface name e.g. eth0/arp_filter = 1
>
> As an aside, I would also recommed setting up different VLANs, if your
> switch support them. That way you can get different "logical"
switches.
>
> Regards,
> -Varun
>
> Marco Berizzi wrote:
> > Hello everybody.
> >
> > I have a problem with my firewall rules on my Slackware Linux box
9.0
> > (kernel 2.4.20-xfs).
> > This system is configured with 3 NIC (one for the router, one for
the
> > dmz, and the other for the private net).
> > I have written a firewall (iptables) that is processing packet based
> > also on the incoming interface.
> > This firewall is connected in a not good environment where all the
NIC
> > (and the router) are connected to the same switch (don't ask me
why).
> > Here is the problem: an incoming packet from the private net
sometimes
> > is catched by the priv NIC, sometimes is catched by the DMZ nic and
> > sometimes is catched by router NIC. This happens (I think) because
when
> > a client (windoze) sends an arp request with the priv NIC IP, linux
> > replies with the MAC address from any of the 3 NIC and not only with
the
> > MAC from the priv NIC.
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