Where does an incoming call to an international number come from from my own IP address?

Question

Asterisk

I'm sitting, not touching anyone, when suddenly an endless sequence of incoming calls begins.
You drop it - a new one immediately begins.
The IP address is mine. Number 6500 does not exist on the PBX.
In the log file /var/log/asterisk/full there is not a single mention of either the 6500 account or the dialed international one, only its authorization is visible by IP.
The CDR report is also empty.

The dialer displays it like this:


Tell me, please, where to dig?

Asterisk 13.7.2
FreePBX 13.0.197.28
MicroSIP

Answer 1

Does the call land on your desktop with a SIP client but not go through your Asterisk?
If yes, then your desktop either has a public IP, or "port forwarding" is organized in the NAT on the router, or NAT works in the "Port Restricted Cone" mode and packets from "intruders" fly through the session already open between you and the legitimate PBX.

Answer 2

https://habr.com/ru/company/myasterisk/blog/130325/
rule 5e

Answer 3

Typical search and search for holes in order to call for free.
Block calls from unregistered numbers Turn on
TLS at least for signaling
Hide internal networks in VPN
Use non-standard ports