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From: Martijn Lievaart <m@rtij.nl>
To: Vincent Arniego <vincent_arniego@yahoo.com>
Cc: netfilter@vger.kernel.org
Subject: Re: [NFQUEUE] Help with program that changes DHCP payload
Date: Wed, 30 Jan 2008 22:22:37 +0100	[thread overview]
Message-ID: <47A0EA9D.2010705@rtij.nl> (raw)
In-Reply-To: <763049.9097.qm@web58311.mail.re3.yahoo.com>

Vincent Arniego wrote:
>
> Hi Everyone,
>
> I'm kinda new here and I would like some help regarding
>  netfilter_queue. If this is asked already, forgive me I didn't see it in the archives.
>
> I'm making a program that changes the value of an attribute in the DHCP
>  payload.
> I'm using nfqueue to intercept the packet, change the content of the
>  payload and resend it again to DHCP
> which resides in the same server as the firewall. Why am I doing this?
>  I'm making a pseudo option 82 using a translated bridge (which the mac
>  is unchangeable) but I'm using the hostname attribute instead.
>   

Stop right there. The ISC DHCP server does very funky stuff to see 
packets addressed to 0.0.0.0. This means those packets do not go through 
netfilter. I bet this is at the root of your problem.

I cannot think of a quick way to change this. Maybe hacking at dhcrelay 
sources is an better option.

HTH,
M4


  parent reply	other threads:[~2008-01-30 21:22 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-01-30  3:58 [NFQUEUE] Help with program that changes DHCP payload Vincent Arniego
2008-01-30 13:28 ` Ashok Rao
2008-01-30 21:22 ` Martijn Lievaart [this message]
  -- strict thread matches above, loose matches on Subject: below --
2008-01-31  5:56 Vincent Arniego
2008-01-31  6:02 Vincent Arniego

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