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From: Antony Stone <Antony@Soft-Solutions.co.uk>
To: netfilter@lists.netfilter.org
Subject: Re: DHCRELAY through IPTABLES Firewall
Date: Tue, 29 Oct 2002 13:03:17 +0000	[thread overview]
Message-ID: <200210291303.g9TD3Ne10065@vulcan.rissington.net> (raw)
In-Reply-To: <004201c27f3d$20c88520$8f33e40f@lsmith5953>

On Tuesday 29 October 2002 11:20 am, bigman@monster-solutions.net wrote:

> below is what gets logged when using DHCRELAY. It looks like it will work
> but then I never see the request from the 192.168.2.69 (firewall) hit the
> DHCP server which I am running a sniffer on. I must be making this harder
> then it should be. Can you provide me with the steps to get DHCRELAY
> working across different subnets. I really appreciate all of the help.
>
> Oct 29 07:13:12 firewall kernel: IN=eth2 OUT=
> MAC=ff:ff:ff:ff:ff:ff:08:00:09:f1:b2:ba:08:00 SRC=0.0.0.0
> DST=255.255.255.255 LEN=328 TOS=0x00 PREC=0x00 TTL=128 ID=8523 PROTO=UDP
> SPT=68 DPT=67 LEN=308

Packet comes in on eth2 with broadcast destination IP and MAC adresses, 
source IP address = 0.0.0.0

> Oct 29 07:13:12 firewall kernel: IN= OUT=eth2 SRC=192.168.2.69
> DST=192.168.1.70 LEN=328 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=67
> DPT=67 LEN=308

The the firewall sends a packet from its own IP address 192.168.2.69 to the 
DHCP server 192.168.1.70 on *eth2* !!!

Why ?

> Oct 29 07:13:27 firewall kernel: IN=eth2 OUT=
> MAC=ff:ff:ff:ff:ff:ff:08:00:09:f1:b2:ba:08:00 SRC=0.0.0.0
> DST=255.255.255.255 LEN=328 TOS=0x00 PREC=0x00 TTL=128 ID=8537 PROTO=UDP
> SPT=68 DPT=67 LEN=308

DHCP client hasn't had an answer within 15 seconds so it asks again.

> Oct 29 07:13:27 firewall kernel: IN= OUT=eth2 SRC=192.168.2.69
> DST=192.168.1.70 LEN=328 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=UDP SPT=67
> DPT=67 LEN=308

Firewall sends the request to 192.168.1.70 out of the wrong interface again.

Antony.

-- 

Normal people think "if it ain't broke, don't fix it".
Engineers think "if it ain't broke, it doesn't have enough features yet".


  reply	other threads:[~2002-10-29 13:03 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-10-27  4:33 DHCRELAY through IPTABLES Firewall bigman
2002-10-27  8:09 ` Antony Stone
2002-10-27  8:58   ` bigman
2002-10-28  8:49     ` Antony Stone
2002-10-28 10:36       ` bigman
2002-10-28 10:54         ` Antony Stone
2002-10-28 11:26           ` bigman
2002-10-28 11:39             ` Antony Stone
2002-10-29  7:37               ` bigman
2002-10-29  9:15                 ` Antony Stone
2002-10-29 11:20                   ` bigman
2002-10-29 13:03                     ` Antony Stone [this message]
2002-10-30  0:30                       ` bigman
2002-10-30  0:41                         ` Antony Stone
2002-10-30  7:15                           ` bigman
2002-10-29 10:02                 ` bigman
2002-10-29 10:29                   ` Antony Stone
2002-10-29 11:44                     ` bigman

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