Asterisk eats all CPU

Network problem

Change to correct ip in /etc/asterisk/h323.conf, restart Asterisk

DDOS attack

Unload chan_sip.so module. If it helps - proceed.

Load module back. Check sip debug. If a lot of packets come from one IP - block it.

Check if it helps.

Broken code

Check with: http://www.moythreads.com/wordpress/2009/05/06/why-does-asterisk-consume-100-cpu/

Investigate the module which causes it.

If not critical (like IAX2) -> unload it and check if it helps. Rinse and repeat if not.