Random calls on extension from 3030 and 67?

I keep getting calls from number 3030 in frequent intervals on my SIP extension. Is it an attack or some wrong configuration ?
I have not setup any extension with the number 3030 or 67.


is port 5060 open to the world? Do you allow anonymous SIP calls? If so, block both.

I allow anonymous SIP calls. After blocking that, I stopped getting these calls. But, I have a DID number and would like to get calls from outside.

Why do you need to allow anonymous SIP calls to get calls to your DID?
Does your SIP provider require that?