Security Basics mailing list archives
RE: Caching a sniffer
From: "David Gillett" <gillettdavid () fhda edu>
Date: Thu, 25 Mar 2004 11:55:26 -0800
-----Original Message----- From: Shawn Jackson [mailto:sjackson () horizonusa com]I think this suggestion was that the MAC flood would trigger the aging, so it keeps pace automatically. That, in turn, requires the malicious host that's flooding bogus MAC addresses to continue doing so, in order to try to keep valid MACs from being retained in the table (long enough to keep their traffic from flooding and being seen by the sniffer).So there would need to be a algorithm to detect the MAC flood and respond by increasing the age time for records in the table. Once the flood stops aging would return to normal. Correct?
Not really. I'm a switch, and I've just seen a new source MAC address, which I want to insert into my table. Uh-oh, the table is full. Instead of just failing to learn the new address, I'll "age out" the oldest address in the table prematurely to make space for the new one. (If I track their ages so I can age them out normally, finding the oldest one shouldn't be any problem.) I didn't "detect the flood" or alter the normal aging time. I just discarded some old information instead of discarding the new information just received. (In essence, this means treating the MAC table like a FIFO cache.) David Gillett
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Current thread:
- RE: Caching a sniffer, (continued)
- RE: Caching a sniffer David Gillett (Mar 25)
- RE: Caching a sniffer Shawn Jackson (Mar 25)
- RE: Caching a sniffer Andrew Shore (Mar 25)
- RE: Caching a sniffer Paul Blackstone (Mar 25)
- RE: Caching a sniffer Byron Copeland (Mar 26)
- Re: Caching a sniffer Aaron (Mar 29)
- RE: Caching a sniffer Paul Blackstone (Mar 25)
- RE: Caching a sniffer David Gillett (Mar 25)
- RE: Caching a sniffer Andrew Shore (Mar 25)
- RE: Caching a sniffer Shawn Jackson (Mar 25)
- RE: Caching a sniffer Shawn Jackson (Mar 25)
- RE: Caching a sniffer David Gillett (Mar 26)
- RE: Caching a sniffer Shawn Jackson (Mar 25)
- RE: Caching a sniffer David Gillett (Mar 25)
- RE: Caching a sniffer Shawn Jackson (Mar 25)
- RE: Caching a sniffer Andrew Shore (Mar 25)
- RE: Caching a sniffer Shawn Jackson (Mar 25)
- RE: Caching a sniffer David Gillett (Mar 26)
- RE: Caching a sniffer Shawn Jackson (Mar 26)
- RE: Caching a sniffer Shawn Jackson (Mar 26)
- RE: Caching a sniffer Nero, Nick (Mar 26)
- Re: Caching a sniffer aruna (Mar 29)