Re: snort inline (non-drop mode) br0

["Lawrence R. Hughes, Sr." <lhughes () safemedia com>]

Joel,

Sorry If I did not provide the info you need.here it is: snort 2.8.6.1  

 We are experiencing a large percentage of dropped packet. dropped packets start very low, but on the increase all the 
time exceeding 70%. please see attached startup and  perf. monitor report

2.       We see a large number of open sessions  without any reduction.  see attached perf. monitor  and attached 
config file

3.       Only 7 rule groups are applied

4.       We have disabled many preprocessors and so rules in an attempt to debug the dropped packet problem??

5.       We do not detect duplicate traffic, snort is running on BR0 which is made of eth0 and eth1.

6.       Snort is not on a network tap.running inline without blocking.

7.       We are detecting alerts which are valid alerts.

8.       Machine is duel core, 16GB memory @1333Ghz, fSB 1333Ghz, nic on PCI 2.0 5GBs, Raid SAS 15000RPM

 

The issue is the dropped packets...i hope the attached files provide you with enough info to be able to help

 Thanks,

Larry

  ----- Original Message ----- 
  From: Joel Esler 
  To: Lawrence R. Hughes, Sr. 
  Cc: snort-users () lists sourceforge net 
  Sent: Tuesday, February 01, 2011 1:45 PM
  Subject: Re: [Snort-users] snort inline (non-drop mode) br0


  Lawrence,


  I keep seeing you post to the list asking about open sessions.  But I never see any responses to anyone's questions 
that we ask.


  Are you having a problem with open sessions, or are you perceiving it to be a problem?  What's the problem?  Are you 
dropping packets?  Are you seeing duplicate traffic?


  Is Snort not detecting things?  What's the issue?


  Joel


  On Tue, Feb 1, 2011 at 12:59 PM, Lawrence R. Hughes, Sr. <lhughes () safemedia com> wrote:

    Hi,

    We use snort inline in the non-drop mode and our sensor is listens on br0.
    Could it be that we detect the 3whs (session) with stream5, but don't detect when the session has ended, thus 
giving us a high rate of open sessions?

    If this is the case, then what interface would be better to use eth0 or eth1 (currently both eth0 & eth1 are 
configed to give us br0) ?

    Thanks,
    Larry


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  -- 
  Joel Esler
  Skype:eslerjoel
  http://blog.snort.org && http://blog.clamav.net

Attachment: sipsips.conf
Description:

Attachment: perfmonitor.dat
Description:

------------------------------------------------------------------------------
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Finally, a world-class log management solution at an even better price-free!
Download using promo code Free_Logger_4_Dev2Dev. Offer expires 
February 28th, so secure your free ArcSight Logger TODAY! 
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