And when you do set up such an arrangement, depending on the number of rules you turn on, you can generate truly massive volumes of data to be analyzed by ACID or other tools.  It is relatively easy to deploy snort for large volume, small number of rules type deployments.  Aside from scaling the collectors and management console themselves, it can even be a challenge to aggregate all that data in a WAN deployment.

IDS has to be aimed carefully and then fired.  And then one needs to ask what the derived value is, and just how you’re going to deal with the info.  The latter being a magnificent operational challenge.

Or that’s at least been my experience. YMMV.




On 6/9/05 1:31 PM, "Jordan Medlen" <jmedlen@sagonet.com> wrote:

We just finished deploying a Snort IDS system on our network. The task of doing so was well worth the effort, and quite a bit of effort and resources were needed for our deployment. Due to the fact that we have a sustained 5Gbps of traffic to monitor in our Tampa data center alone, a simple server running Snort was just not going to cut it and rather than deploying off of our core routers in Tampa, which would catch inbound and outbound traffic, we decided after our testing that placing our tap points on our core routers was just not going to be sufficient due to the amount of abuse we saw in testing between customers in our facility. We decided to build a single server for each of our distribution switches at all of our locations that would communicate to a central server running the ACID console. This deployment has allowed us to gather so much information about what *TRULY* is and has been going on, that we wonder why we didn’t do this sooner.
 
Please keep in mind that there are many right ways to deploy an IDS system, however only one is really going to fit *most* of your needs initially. With some time, patience, and quite a bit of caffine, you should be well on your way to dropping your abusive traffic on your network. Good luck to you!
 
--
Jordan Medlen
Chief Network Engineer
Sago Networks
 

From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] On Behalf Of Drew Weaver
Sent: Thursday, June 09, 2005 11:46 AM
To: nanog@merit.edu
Subject: Using snort to detect if your users are doing interesting things?
          Howdy, I am not sure if this is the proper place, if not I’ve noticed you guys know what to do so I’ll put the fire retardant suit on now. Recently due to growth we have seen an influx of “different” and “interesting” types of characters ending up on our network. They like to do all sorts of things, port scan /8s spam, setup botnets with the controllers hosted on my network.. etc. I’m wondering what is the best way to detect people doing these things on my end. I realize there are methods to protect myself from people attacking from the outside but I’m not real sure how to pinpoint who is really being loud on the inside.
 
I did have one somewhat silly question.. if you look at the statistics of a Fast Ethernet port, and it is doing both 2000 pps out, and 2000 pps in (pretty much equal in/out) but hardly any bandwidth at all can anyone think of a single application that would mimic that behavior?
 
Sorry if this is elementary network school knowledge.
-Drew


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