From: Giles Coochey <giles@coochey.net>
To: Srinivasa T N <seenutn@linux.vnet.ibm.com>
Cc: netfilter@vger.kernel.org, ABC <abc@telekom.ru>
Subject: Re: Double rules for using NETFLOW?
Date: Wed, 02 Feb 2011 11:09:18 +0100 [thread overview]
Message-ID: <4D492D4E.4060106@coochey.net> (raw)
In-Reply-To: <4D492B87.5050008@linux.vnet.ibm.com>
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On 02/02/2011 11:01, Srinivasa T N wrote:
> Hi All,
> I am using ipt_NETFLOW 1.7 on my RHEL 6 (2.6.32) box. Now if I
> want to accept packet destined for some port and at the same time I
> want it to be accounted also, then I have to use the following rules:
>
> iptables -A INPUT --dport <portnum> -j NETFLOW
> iptables -A INPUT --dport <portnum> -j ACCEPT
>
> This makes that every packet that I accept should have two rules
> (one for accepting and one for accounting). Don't you people think
> that it will increase the number of rules a packet has to traverse?
> Or is my understanding wrong?
>
umm... more actions on packets = more processing... so yes, Netflow
accounting will produce a CPU overhead.
No such thing as a free lunch :-)
--
Best Regards,
Giles Coochey
NetSecSpec Ltd
NL T-Systems Mobile: +31 681 265 086
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next prev parent reply other threads:[~2011-02-02 10:09 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-02 10:01 Double rules for using NETFLOW? Srinivasa T N
2011-02-02 10:09 ` Giles Coochey [this message]
2011-02-02 17:56 ` Grant Taylor
2011-02-03 5:15 ` Srinivasa T N
2011-02-03 20:14 ` Grant Taylor
2011-02-04 5:02 ` Srinivasa T N
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