THIS : http://etel.wiki.oreilly.com/wiki/index.php/SIP_DoS/DDoS_Mitigation
also works quite well for these attacks..

they wont stop the brute force ( you will need to configure fail2ban for that )
but this will setup iptables to rate limit any sip connections, so your pc wont get that loaded.

you can thank Kristian Kielhofner ( a member of the FS community ) for that neat little script :)

maybe we can copy that script ( Kristian ?? ) to the Freeswitch wiki..
( with a few modifications )..

be careful of the STOP command on that script its defective ! 
( and will wipe all firewall rules, especially dangerous if you drop all by default )

Jay


On Mon, Aug 9, 2010 at 5:03 PM, Jan Berger <jan.berger@video24.no> wrote:

1) It stucks on one CPU even I have 2 core since sofia-sip is single
threaded ?

Your FS uses a single process, and the operating systems need multiple
processes to fully utilize multiple cores. It's major difference between
threads and processes on this.

Jan



--
Sincerely

Jay