Hardware capture platforms
warren at kumari.net
Wed Jul 30 13:32:31 CDT 2008
On Jul 29, 2008, at 10:43 PM, Darryl Dunkin wrote:
> Hubs sure are fun...
This might be a stupid question, but where can one get small hubs
these days? All of the common commodity (eg: 4 port Netgear) "hubs"
these days are actually switches.
What I am looking for is:
Small enough to live in my notebook bag (e.g.: 4 port with a wall wart.)
While a tap would work, I'd prefer a hub because I can then use it to
connect machines together in a pinch.
In the past I have bought some cheap 4 port commodity switches (form
Circuit City or somewhere similar), found the datasheet for the
chipset (it was a Broadcom something or other) and tied the pin to
ground that disables the learning mode (actually, I think that the pin
just set the size of the learning table to be 0 entries). While this
works, doing it once was more than enough :-)
> I would trunk the ports you are monitoring, and run the port monitor
> the trunk port instead (one trunk port, one port per VLAN, plus one
> span) which will help with your density. This is assuming the analysis
> software you have can read the dot1q tags, but means you do not need
> burn two ports per monitor.
> -----Original Message-----
> From: James Pleger [mailto:jpleger at gmail.com]
> Sent: Tuesday, July 29, 2008 19:26
> To: nanog at merit.edu
> Subject: Re: Hardware capture platforms
> There are several things that you can do with open source solutions,
> however looking at the data may be a bit more difficult than something
> like Network Generals or Solera Networks capture appliances. It is
> still doable and is definitely much much cheaper...
> Something you might want to look into is traffic aggregation with a
> switch or hub. You can buy an Allied Telesyn switch and basically turn
> it into a hub by disabling switchport learning. Just an idea.
> You can use regular old tcpdump with the -C option to rotate logs
> tcpdump -i blah -s0 -C <filesize to rotate>, etc.
> or you can use Daemonlogger which does pretty much the same thing...
> On Tue, Jul 29, 2008 at 6:45 PM, Network Fortius
> <netfortius at gmail.com>
>> Richard's blog @ http://taosecurity.blogspot.com/search?q=taps and
>> especially his books (Tao of Network Security Monitoring and
>> Detection) are the best sources I have ever found, concerning [not
>> taps and[/but] so much more on the subject - proper usage and best
>> methodologies and practices for network monitoring (and not only for
>> On Tue, Jul 29, 2008 at 7:12 PM, Christopher Morrow
> <morrowc.lists at gmail.com
>>> On Wed, Jul 30, 2008 at 12:35 AM, Jared Mauch
>>> <jared at puck.nether.net>
>>>> Check out packet forensics depending on what your ultimate
>>> I would also add a 'see packet forensics'...
>>>> On Jul 29, 2008, at 7:10 PM, "John A. Kilpatrick"
> <john at hypergeek.net>
>>>>> We've deployed a bunch taps in our network and now we need a
> platform on
>>>>> which to capture the data. Our bandwidth is currently pretty low
>>>>> got 8 links to tap, which means I need 16 ports. Has anyone done
>>>>> research on doing accurate packet capture with commodity hardware?
>>>>> John A. Kilpatrick
>>>>> john at hypergeek.net Email|
>>>>> john-page at hypergeek.net Text pages| ICQ: 19147504
>>>>> remember: no obstacles/only challenges
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