Snort mailing list archives
Re: Performance and rule tuning
From: "Jefferson, Shawn" <Shawn.Jefferson () bcferries com>
Date: Wed, 3 Dec 2008 12:57:25 -0700
I've been running the mmaped pcap module with snort on both my sensors for the last two days, and noticed quite an improvement, however I was still getting dropped packets. I commented out all the Emerging Threats rules and this eliminated any dropped packets with over 100 MB/s of sustained traffic (at least that is what snort stats is showing me.) Also, I noticed CPU usage went down considerably as well. I guess I don't have enough horse power to run these rules. Speaking of the stats though... I noticed that with each increase in the performance of my snort sensor, I'm recording more MBit/second. Now it's up to around 150 Mb/s. Is this number an accurate measure of what's on the wire, or does it depend somewhat on the performance of your sensor? One more question about rule tuning: I am getting some false positives from the ftp pre-processor. How do I suppress these without disabling the pre-processor altogether? Thanks! Shawn -----Original Message----- From: Jefferson, Shawn [mailto:Shawn.Jefferson () bcferries com] Sent: December 02, 2008 11:40 AM To: Snort-users () lists sourceforge net Subject: Re: [Snort-users] Performance and rule tuning Thanks for your help everyone, I think I have this working. The log was daemon.log not messages, and it wasn't using PCAP_FRAMES. I did the following: Apt-get remove libpcap0.8 Rebuilt snort Used "export PCAP_FRAMES=32768" (I was confused as to use export or not... export seems to be required.) Now it says "Using PCAP_FRAMES=32768" in daemon.log. Now I'll do this on my main snort sensor and see if there is any performance improvement. ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Snort-users mailing list Snort-users () lists sourceforge net Go to this URL to change user options or unsubscribe: https://lists.sourceforge.net/lists/listinfo/snort-users Snort-users list archive: http://www.geocrawler.com/redir-sf.php3?list=snort-users
Current thread:
- Performance and rule tuning Jefferson, Shawn (Dec 02)
- Re: Performance and rule tuning (linux) Phil Wood (Dec 02)
- <Possible follow-ups>
- Re: Performance and rule tuning Nathaniel Richmond (Dec 02)
- Re: Performance and rule tuning Jefferson, Shawn (Dec 02)
- Re: Performance and rule tuning Jefferson, Shawn (Dec 03)
- Re: Performance and rule tuning Matt Jonkman (Dec 03)
- Re: Performance and rule tuning Joel Esler (Dec 03)
- Re: Performance and rule tuning Jefferson, Shawn (Dec 04)
- Re: Performance and rule tuning Joel Esler (Dec 04)
- Re: Performance and rule tuning Todd Wease (Dec 04)
- Re: Performance and rule tuning Jefferson, Shawn (Dec 02)