There are outgoing calls on unconfigured extensions on my box

Hi guys.

I have an Asterisk PBX configured at a client. I used the FreePBX Distro for a quick set-up. Everything on the box is fully up-to-date.

The client is only a single guy with a single phone. The phone is configured on extension 201, the only extension on the box. Still, there are about 10 - 20 calls/hour going out with CID’s that are not even configured on the box (4-digits, 7 digits, ‘admin11’, etc…). CDRs show “s [from-sip-external]” as destination. The firewall is as tight as possible on both the box and the router. On the router, only a range of 30 ports is opened for RTP voice signalling. 5060 is closed as well as all other ports.

How is this possible? I have a vague idea this could caused by the way I configured the dial plan. I only have one rule with just a dot “.” to allow all calls through.

Anyone got an idea? Thanks a million in advance.

You are probably allowing “guest” or “anonymous” calls, your port 5060/UDP is however open to whatever host is connectring, whether you like it or not . . .

Alright, a few minutes after I posted I disabled “Allow SIP guests” under “Asterisk SIP Configuration” and I haven’t seen any calls in CDR since. Guess that was it, thanks!

That function should be disabled from default, so many people get caught out by it.