Ethical Hacking

Learn to find vulnerabilities before the bad guys do! Gain real world hands on hacking experience in our state of the art hacking lab. Course designed and taught by expert instructors with years of penetration testing experience. 12 student maximum in every class. Certification attempt included in every package.
Computer Forensics Training at InfoSec Institute

Gain the in-demand skills of a certified computer examiner, learn to recover trace data left behind by fraud, theft, and cybercrime perpetrators. Discover the source of computer crime and abuse at your organization so that it never happens again. All of our class sizes are guaranteed to be 12 students or less to facilitate one-on-one interaction with one of our expert instructors.




Network Security Snort-Users
[Top] [All Lists]

[Snort-users] Tweaking promiscous mode sniffing performance

Subject: [Snort-users] Tweaking promiscous mode sniffing performance
Date: Wed, 29 Sep 2004 10:47:48 +0200 (CEST)

I'm trying to get the most out of my FreeBSD 4.x machine, and now I have a
question:


When an interface is put into promiscous mode, it forwards all received
packets to the kernel. The kernel (the IP stack) will check each packet to
see if it is addressed to the local machine.

My snort is listening to a Span-port which generate about 600 Mbps of
traffic. Not a single one of these billions of packets are addressed to
the sniffer machine.

I think it is pretty unneccesary for the kernel to waste CPU on all these
packets. (not only is the IP stack checking them, maybe you have a
firewall and ipsec configuration that the billions of packets are matched
against)

Is there any way to tell the kernel not to process the incoming packets on
a given interface, while sniffer programs still can read the raw data?


(My sniffer interface have no IP address.
Another interface, the management interface, do have an IP address and on
that interface I want the kernel to process all packets.)

/Elof



-------------------------------------------------------
This SF.net email is sponsored by: IT Product Guide on ITManagersJournal
Use IT products in your business? Tell us what you think of them. Give us
Your Opinions, Get Free ThinkGeek Gift Certificates! Click to find out more
http://productguide.itmanagersjournal.com/guidepromo.tmpl
_______________________________________________
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

<Prev in Thread] Current Thread [Next in Thread>
  • [Snort-users] Tweaking promiscous mode sniffing performance, Martin Olsson <=