Following this asipto guide:
http://kb.asipto.com/asterisk:realtime:kamailio-4.0.x-asterisk-11.3.0-astdb
I've found that no auth is required to create a communication: Invites are
sent regardless of a previously done auth with the kam's auth_db
I've used this sip checker:
http://www.sinologic.net/proyectos/asterisk/checkSecurity/
Result:
Uh oh! you allow external calls...
Configure better your sip configuration to avoid this calls
SIP/2.0 100 trying -- your call is important to us
What is missing in the config file explained in the guide?
Manuel