[Snort-users] Re: Snort in a switched environment

Joe Pampel joe at ...3851...
Wed May 15 10:01:04 EDT 2002


1. - re: Bruno's solution. I did this for a long time. Only real drawback from a practical point of view is if you have redundant paths you need 2 hubs or else you've built a new SPF..

2. Saw Cisco config, so thought I'd post what Nortel 350/450 looks like:
(view in courier). This is under switch configuration-->Port Mirroring configuration

    Port Mirroring Configuration


                     Monitoring Mode:  [ <-> Port X   and   Port Y <-> ]
                   Monitor Unit/Port:  [ 1/9  ]

                         Unit/Port X:  [ 1/8  ]
                         Unit/Port Y:  [ 2/8  ]

                           Address A:  [ 00-00-00-00-00-00 ]           
                           Address B:  [ 00-00-00-00-00-00 ]           


                Currently Active Port Mirroring Configuration
                ---------------------------------------------
Monitoring Mode: <-> Port X   and   Port Y <->   Monitor Unit:  1 Port:  9
Unit X:  1  Port X:  8   Unit Y:  2  Port Y:  8                     


This is the port mirroring config screen. In this particular example there are 2 switches in cascade (linked). The monitor port is unit 1, port 9. It is monitoring all traffic in and out (<->) of unit 1 port 8 and unit 2 port 8. 

The older versions of the Nortel code don't (AFAIK) support mirroring multiple ports, but software & firmware upgrades are *free* from Nortel for the 350/450.  Last pertinant detail - the monitoring port is unreachable so you need another NIC to be a normal "comm" NIC so you can talk to the sensor, have it log etc. 

hth

Joe






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