Hi, I have facing this issue from 3CX v 15.5 on Debian 9.4
As we have config to only open port 5060,5090 on IPTable to some specific trust source IP only. But after save IPTable file and reboot server, seem 3CX PBX auto add rule to Open Port 5060,5090 to ALL on IPTable
As 2 this line:
-A INPUT...