Snort IDS + TAPS

From: Eric Hines (eric.hines_at_appliedwatch.com)
Date: 11/12/03

  • Next message: Chris Reining: "Re: Snort IDS + TAPS"
    Date: Wed, 12 Nov 2003 13:23:45 -0800
    To: focus-ids@securityfocus.com
    
    

    All:

    We are deploying Snort on a two interface appliance, connected to a GigE
    Netoptics Ethernet TAP. By design, TAPs are split up into (2) monitoring ports,
    (RX split up between two ports):

    INTERFACE 1 - (from router -> switch) [ ]
    INTERFACE 2 - (from switch -> router) [ ]

    Obviously because the RX is split up between 2 ports, if we bind Snort to
    interface 1, it will only see traffic from ROUTER -> SWITCH. If we bind Snort
    to inteerface 2, it will only see traffic from SWITCH -> ROUTER. Therefore, we
    must bind Snort to both interfaces to see both sides of the session. Here's
    where the problem is. If 2 separate Snort processes are monitoring two
    interfaces, how is the Snort on each interface going to maintain state for all
    the connections? Each snort process only sees 1/2 of the connection!

    I've spoken to someone that has said Snort requires modification to listen on a
    tapped device because of this very issue. Someone please advise.

    -------------------------------------------
    Eric Hines
    CEO, Chairman
    Applied Watch Technologies, Inc.
    web: http://www.appliedwatch.com
    email: eric.hines@appliedwatch.com
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  • Next message: Chris Reining: "Re: Snort IDS + TAPS"

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