Snort mailing list archives
Re: Quick questions about recieved packets
From: sekure <sekure () gmail com>
Date: Wed, 26 Oct 2005 10:51:42 -0400
Do you know approximately how much traffic you are trying to monitor? Definitely make use of the MMAPed pcap library recommended by someone already, i saw some drastic improvements with it. Also, enable perfmonitor, tell it to dump stats every minute or so and let it run for 30 minutes. This will give you a better idea of the throughput and the CPU utilization. Post those results back to the list When all else fails, you can start disabling rule sets. Do you really need every single rule enabled? On 10/26/05, Joseph Nicholson <wjnicholson () gmail com> wrote:
These are onboard NIC's that came with the board I got from Supermicro. 2 x Intel(r) 82541 Gigabit Ethernet Controllers I have been thinking about adding a PCI NIC just to see if there is a difference. On 10/26/05, Joshua Berry <JBerry () penson com> wrote:What kind of NIC's are you using on the Sensor? I have had some issueswith certain cards (mostly Realteks) on Linux, the Intel NIC's seem to work the best and you can enable device polling (NAPI) in the kernel for some of these cards as well which will boost performance.________________________________From: snort-users-admin () lists sourceforge net [mailto: snort-users-admin () lists sourceforge net] On Behalf Of Joseph NicholsonSent: Wednesday, October 26, 2005 8:25 AM To: snort-users () lists sourceforge net Subject: Re: [Snort-users] Quick questions about recieved packets I was afraid of that. I have snort plugged into a Cisco 3560G Switch on a mirrored port. I ammirroring 10 other ports on the switch currently. This is my core switch and brings about 5 different network segments together. I am using the Official Snort Rules and the Bleeding Snort Rules. Snort is setup to kick out the Alerts via Syslog. The local Syslog function in Linux is setup to send the Alerts to a Syslog appliance that parses all of my logs for me.For testing I setup Snort to output Alerts via unified logging and thatdidn't help any. I currently have both Tx and Rx being mirrored to my monitoring port. I tried just Tx and just Rx and got the same result. The monitor port is a Gigabit port and the monitoring ethernet port is running at a Gigabit also. On the linux appliance that port is running in promiscuous mode and has no IP. I have a management interface on the box also that I use to send the syslog files across and that I log into to manage the box.Any thoughts or suggestions would be appreciated. This is the firstproduction Sensor I have setup. All my testing sensors apparently didn't have enough traffic being pushed at them.On 10/26/05, Richard Bejtlich <taosecurity () gmail com > wrote:Joseph Nicholson wrote:I see that snort dropped 179457 packets because it couldn't processthem.Snort received 186246 packets Analyzed: 6789(3.645%) Dropped: 179457(96.355%) My gut instinct is telling me that it dropped 179457 packets becauseitfelt there was no threat from them and that the 6789 it analyzedlookedsuspicious.Hi Joseph, You have a serious problem with your Snort deployment. The packets Snort dropped were never inspected, period. Can you describe your configuration? Are you sending Snort alerts directly to a database, without Barnyard? Are you running any odd rules? Sincerely, Richard http://www.taosecurity.com-- Joseph Nicholson-- Joseph Nicholson
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Current thread:
- Quick questions about recieved packets Joseph Nicholson (Oct 25)
- <Possible follow-ups>
- Re: Quick questions about recieved packets Richard Bejtlich (Oct 26)
- Re: Quick questions about recieved packets Joseph Nicholson (Oct 26)
- Re: Quick questions about recieved packets Murali Raju (Oct 26)
- Re: Quick questions about recieved packets Bill Parker (Oct 26)
- Re: Quick questions about recieved packets Joseph Nicholson (Oct 26)
- RE: Quick questions about recieved packets Joshua Berry (Oct 26)
- Re: Quick questions about recieved packets Joseph Nicholson (Oct 26)
- Re: Quick questions about recieved packets sekure (Oct 26)
- Re: Quick questions about recieved packets Joseph Nicholson (Oct 26)
- Re: Quick questions about recieved packets Joseph Nicholson (Oct 26)
- Re: Quick questions about recieved packets sekure (Oct 26)
- Re: Quick questions about recieved packets Joseph Nicholson (Oct 26)
- Re: Quick questions about recieved packets Joseph Nicholson (Oct 26)