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Date:      Tue, 12 Sep 2006 13:45:11 -0700
From:      Chuck Swiger <cswiger@mac.com>
To:        Bart Silverstrim <bsilver@chrononomicon.com>
Cc:        FreeBSD Mailing Lists <freebsd-questions@freebsd.org>
Subject:   Re: forwarding as a gateway, logging certain traffic
Message-ID:  <DCD90032-CBF1-45A7-A0FA-EB7B15F1733E@mac.com>
In-Reply-To: <CC7F9A36-1D5B-4064-9E55-7D3A2E36CAB5@chrononomicon.com>
References:  <7269D41C-C334-44DC-9549-ACB28F79014A@chrononomicon.com> <20060912160830.b7a91061.wmoran@collaborativefusion.com> <B7DDE980-7DB8-4AB8-AA85-8FD89638469C@mac.com> <CC7F9A36-1D5B-4064-9E55-7D3A2E36CAB5@chrononomicon.com>

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On Sep 12, 2006, at 1:37 PM, Bart Silverstrim wrote:
>> Better to use something like:
>>
>> 	ipfw add 1 log tcp from any to me 25 setup
>>
>> If Bart would like to use tcpdump for the same purpose, consider  
>> running something like:
>>
>> 	tcpdump -nt 'port 25 and (tcp[tcpflags] & tcp-syn != 0)'
>
> Maybe my ipfw is old; it kept telling me that "log" is an invalid  
> action.  However, I think I may be able to get the tcpdump idea to  
> work.

There's a kernel option you need to enable for IPFW to do logging.   
If you're kldload'ing the ipfw module, it probably wasn't compiled  
with IPFW_LOGGING or whatever the exact name is.

Anyway, tcpdump should be your friend.  :-)

-- 
-Chuck




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