Snort mailing list archives
Re: snort and ATM
From: Dragos Ruiu <dr () kyx net>
Date: Wed, 2 Mar 2005 13:05:45 -0800
On March 2, 2005 02:18 am, Teva AVRIL wrote:
So my question is simple : how could i manage to run snort to capture trafic on a atm interface if snort doesn't handle atm? Is it because decapsulation on RedHat9 is made so that snort is able to understand ip packets or something like this? Or maybe the latest libpcap could handle atm now?
Probably something did the reassembly for you. If you need to do it, and you are using AAL5, it's very straightforward if your interface gives you raw cells... (And I assume it _is_ AAL5 as AAL3/4 pretty much went the way of the dinosaurs...) AAL5 segmentation is simple... tack a header and trailer (checksum) on the IP packet, slice it up into 48 byte ATM payloads, add 5 byte ATM header onto each and get 53 byte ATM cells. A bit in the header will indicate the last cell of a packet. Lather Rinse Repeat. Its pretty easy to reassemble those back into IP packets. The code is left as an excercise for the reader :-). Though likely the reassembly is done in hardware and you are getting AAL5 packets and you may just have to strip additional header and trailer off the IP packets to process them in snort. cheers, --dr -- World Security Pros. Cutting Edge Training, Tools, and Techniques Vancouver, Canada May 4-6 2005 http://cansecwest.com pgpkey http://dragos.com/ kyxpgp ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ Snort-users mailing list Snort-users () lists sourceforge net Go to this URL to change user options or unsubscribe: https://lists.sourceforge.net/lists/listinfo/snort-users Snort-users list archive: http://www.geocrawler.com/redir-sf.php3?list=snort-users
Current thread:
- snort and atm Teva AVRIL (Feb 08)
- Message not available
- Re: snort and atm Matt Kettler (Feb 08)
- Message not available
- <Possible follow-ups>
- snort and ATM Teva AVRIL (Mar 02)
- Re: snort and ATM Dragos Ruiu (Mar 02)