Re: Portscan preprocessors dropping packets on a simple nmap-scan

[Ashley Thomas <athomas () cc gatech edu>]

Are you referring to the packet drops reported by snort ?

IMHO, there might be a lot of logging being done, since you are using
nmap to generate a lot of alert causing packets; and excessive logging will
surely overload any IDS. (When you disable portscan preprocessor,
those alerts are not generated, thereby not loading the IDS)

How are you running snort ? (what are the options used ? )

-Ashley

Edin Dizdarevic wrote:

> Hello,
>
> I have a strange situation here: I'm making some tests on a net
> with heavy load. I run simple nmap X/F/N-scans having always some
> packets dropped. I've tried 3 different NICs (Intel/3Com and
> SIS900(Realtek)) and the problem remained. No matter which
> portscan-preprocessor I use, some packets are dropped. Is that normal?
> After deactivating all portscan detection everything is fine. Any docs
> covering that?
>
> Regards,
>
> Edin


--
Ashley Thomas
Research scientist
College of Computing
Georgia Tech.




-------------------------------------------------------
This SF.NET email is sponsored by: FREE  SSL Guide from Thawte
are you planning your Web Server Security? Click here to get a FREE
Thawte SSL guide and find the answers to all your  SSL security issues.
http://ads.sourceforge.net/cgi-bin/redirect.pl?thaw0026en
_______________________________________________
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