Snort mailing list archives
Re: Snort Performance
From: Erek Adams <erek () theadamsfamily net>
Date: Tue, 10 Sep 2002 09:40:14 -0700 (PDT)
On Tue, 10 Sep 2002 jsp1999 () gmx de wrote:
Snort is a great tool that offers convenient ways to customize the network traffic that should be monitored.
Errr... Snort is an intrusions detection program. Network monitoring needs to be left to the likes of ntop and iptraf.
Unfortunately we found out that there is a big problem if nearly all the available rules are used during operation.
Yes, that's right. Why do you think we say "tune your ruleset for your network?" :)
Snort does not look at all the packets, it often simply skips packets. On a highly loaded network this gets worse - more and more packets are simply not analyzed. Isn't this very dangerous, because many exploits require only a few packets to perform an exploit and to compromise machines?
Again, that's why you tune your rules. :) Check the archives, that's been said from day one.
When we had an in depth look at the source code of snort, we saw that there are the RTN and OTN structures for storing the individual rules which have to be iterated through every time a new packet is matched. We consider this not to be optimal, because of the many ANY parts in the source and destination IPs. Has anybody thought about optimizing this basic data structure? Will this be improved in Snort 2.0 (we found some PPT presentations on the web)? Are there any chances for improving the ratio of investigated packets / actual packets on the network?
Why is it not optimal? Care to elaborate? As for the 'any parts', well... We often tell folks to put the more specific rules at the top of the config to improve performance. Please check the archives on this--It's there. :) Snort 2.0 will be different. Many things will have changed. But, we're not there yet. We've got to get 1.9 out of the door before 2.0 can be worried with. Cheers! ----- Erek Adams Nifty-Type-Guy TheAdamsFamily.Net ------------------------------------------------------- This sf.net email is sponsored by: OSDN - Tired of that same old cell phone? Get a new here for FREE! https://www.inphonic.com/r.asp?r=sourceforge1&refcode1=vs3390 _______________________________________________ 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:
- Snort Performance jsp1999 (Sep 10)
- Re: Snort Performance Erek Adams (Sep 10)
- Message not available
- Re: Snort Performance Matt Kettler (Sep 10)
- Re: Snort Performance Erek Adams (Sep 10)
- Re: Snort Performance Matt Kettler (Sep 10)