Solved

IDS implementation/design

Posted on 2009-07-05
3
305 Views
Last Modified: 2013-11-29
We have 3 switches in our building that all connect back to a distribution switch.
The 3 switches on the first floor are Extreme Networks. The distribution switch is a Cisco 4507r

1. What is the easiest way to monitor each switch with an IDS? Do I need a physical connection from the IDS box, to each switch?

2. The inter-vlan routing occurs in the distribution switch (Cisco 4507r). Would it be possible to monitor ALL vlans with port monitoring? Or again, will I need a separate physical connection for each switch and each VLAN.

Using a dell server running RH Enterprise with Snort 2.8.4
Thanks
0
Comment
Question by:WERAracer
  • 2
3 Comments
 
LVL 25

Expert Comment

by:Ken Boone
ID: 24780904
#1  If you want to monitor traffic at a switch level then yes you would need a connection into each switch in your scenario.

#2  Since all intervlan traffic occurs in the 4507 you could monitor all vlans in the 4507.  This will only show you traffic as it flows into the 4507.  Realize that layer 2 or layer 3 traffic that will flow within the same switch will not be seen, however, this is usually sufficient unless there are a few particular ports that you want to make sure you see everything on in one of the remote closets.
0
 
LVL 1

Author Comment

by:WERAracer
ID: 24780923
Ken, thanks for the response. So is it safe to say best practices is to monitor at the VLAN level? Can this be accomplished by enabling port monitoring on trunk ports?

I understand that with this method, we cannot see hosts who talk amongst each other in the same VLAN. We would only see traffic going into the 4507r, destined for other networks. Am I correct by this?
0
 
LVL 25

Accepted Solution

by:
Ken Boone earned 500 total points
ID: 24780951
This is how I typically set it up for my customers.  Try to get the most bang for your buck.  Monitor the vlan, not the trunk.  If I am not mistaken on the 4507 you can mirror the vlans.  I don't think you can mirror the trunk ports.    Also, realize that you won't get 100% of the traffic all of the time.  

Your second statement is correct with the exception of if the traffic is contained within a single vlan, and the traffic still flows through the 4500 because of the way the trunks are set up you will still see the traffic.  
0

Featured Post

Free Tool: Subnet Calculator

The subnet calculator helps you design networks by taking an IP address and network mask and returning information such as network, broadcast address, and host range.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Switched virtual interface on layer 2 switch 2 35
Window update errors on VMs 9 22
EIGRP Bandwidth 9 18
Home firewall recommendations 11 53
If you thought ransomware was bad, think again! Doxware has the potential to be even more damaging.
Knowing where your website is hosted is as important as the features you receive, the monthly fee, and the support you receive. Due diligence should be done when choosing your next hosting provider.
Sending a Secure fax is easy with eFax Corporate (http://www.enterprise.efax.com). First, just open a new email message. In the To field, type your recipient's fax number @efaxsend.com. You can even send a secure international fax — just include t…
Nobody understands Phishing better than an anti-spam company. That’s why we are providing Phishing Awareness Training to our customers. According to a report by Verizon, only 3% of targeted users report malicious emails to management. With compan…

856 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question