Snort mailing list archives
RE: flex response and cisco span ports
From: tyler () ibill com
Date: Wed, 2 Jan 2002 13:30:16 -0500
What type of equipment do you do this on? On a simple 3com switch, you can make a port act like a hub, but cisco's spanning is entirely more complex. You can choose to monitor multiple vlans on one port, therefore how would the port know which vlan to put any sourcing traffic on? tf. -----Original Message----- From: Greg Robinson [mailto:greg () diverdown cc] Sent: Wednesday, January 02, 2002 1:25 PM To: Graeme Fowler; tyler () ibill com; snort-users () lists sourceforge net Subject: Re: [Snort-users] flex response and cisco span ports This is not correct...I use port monitoring and port spanning on my switched networks..and have no problem sending and recieving data on these ports..... ----- Original Message ----- From: "Graeme Fowler" <graeme.fowler () hosteurope com> To: <tyler () ibill com>; <snort-users () lists sourceforge net> Sent: Wednesday, January 02, 2002 12:05 PM Subject: RE: [Snort-users] flex response and cisco span ports
tf wrote:When snort has to respond [ie, send RST packets] I assume it sends them out the interface it is listening on? How does this work when monitoring a cisco switched network? Once I make a port a monitor port, it is read-only and nothing can be sent out on it, so what I've done in the past is put 2 interfaces on my snort sensors. One is a listener, the other is the "management" port that I ssh to, etc, etc.In my experience, this is wrong on both counts. I have successfully used real live machines (both by accident *and* by design; long story) with
real
live IP addresses plugged into a Cisco SPAN (port mirror, monitoring, call it what you will) port on Catalyst 2924XL and 3524/3548XL switches. It can make emergency oh-my-god-everything-broke situations a little more
bearable
if you can sniff *and* make external connections thru the same NIC, especially when you have a laptop with a single interface... and you need
to
just dig that MAC address out of that remote database which is not on your laptop!So I guess my question is this.. Can I make the sensor send it's flex-response packets out the 'mgmt' port instead? Surely there are other people with an environment like this [snort, cisco catalyst switches, flex-response] .. What's everyone else doing?As far as I'm aware, snort chucks its' flexresp packets out via *the
default
gateway* therefore it spits them out thru whatever interface your default route points at. YMMV obviously, but as far back as the initial implementations of flexresp snort didn't do anything too fancy, just generated the packets and dropped them on the IP stack for the kernel to handle as it pleased. I'm not too proud to stand corrected, mind you! Graeme -- Graeme Fowler System Administrator Host Europe Group PLC _______________________________________________ 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
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Current thread:
- flex response and cisco span ports tyler (Jan 02)
- Re: flex response and cisco span ports Greg Herlein (Jan 02)
- <Possible follow-ups>
- RE: flex response and cisco span ports Graeme Fowler (Jan 02)
- Re: flex response and cisco span ports Greg Robinson (Jan 02)
- Re: flex response and cisco span ports Rich Adamson (Jan 03)
- Re: flex response and cisco span ports John Roberds (Jan 02)
- Re: dual nic, was: flex response and cisco span ports Byron (Jan 02)
- Re: flex response and cisco span ports Greg Robinson (Jan 02)
- RE: flex response and cisco span ports tyler (Jan 02)
- RE: flex response and cisco span ports tyler (Jan 02)