From: Marek Kierdelewicz <marek@piasta.pl>
To: lartc@vger.kernel.org
Subject: Re: [LARTC] arp flood (offtopic?)
Date: Wed, 19 Oct 2005 18:04:58 +0000 [thread overview]
Message-ID: <20051019200458.5be5ebf5@cat> (raw)
In-Reply-To: <032b01c5d4bb$a8837ed0$020c0c0a@admin>
> Hi guys,
Hi
>
> Sorry if this is a little offtopic, but I was wandering what can one
> do to prevent/stop arp flooding ?
You can increase arp cache table size:
echo 512 > /proc/sys/net/ipv4/neigh/default/gc_thresh1
echo 2048 > /proc/sys/net/ipv4/neigh/default/gc_thresh1
echo 4096 > /proc/sys/net/ipv4/neigh/default/gc_thresh1
It'll make your box handle arpfloods more easily (at least DoS part).
You can also use static arp entries (man arp). This will ensure known
computers will always have access to (throu) your router (even with
arpflood in progress).
Two solutions mentioned above cope with "Neighbour table overflow" and
problems with accessibility to other legitimate users. They
don't cope however with router's cpu utilisation...
Hope that helps.
Marek Kierdelewicz
KoBa ISP
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next prev parent reply other threads:[~2005-10-19 18:04 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-10-19 14:44 [LARTC] arp flood (offtopic?) Alex
2005-10-19 14:51 ` Carl-Daniel Hailfinger
2005-10-19 18:04 ` Marek Kierdelewicz [this message]
2005-10-19 20:55 ` Alex
2005-10-19 22:09 ` Carl-Daniel Hailfinger
2005-10-20 8:33 ` Oscar Mechanic
2005-10-20 22:19 ` Peter Surda
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