Running FreePBX 15, Distro from Sangoma. All Modules updated and system is currnet.
Allow SIP Guest is off, anonymous is off, CID filter is active. Firewall is only. Random 16digit secret password for extensions and admin access. Have checked for extensions to have wrong IP address of more then 1 IP address. All seems good. No odd SIP accounts or Extensions with odd IP address.
Issue is we periodically get inbound SPAM calls to one of our numbers. These call hit an IVR and they are pressing 1. Once the call is connected they are accessing another SIP Trunk and placing out bound calls. These calls generate about 30-50 calls a second. I do add the CID to the black list, have built a dummy route for the their outbound dialed number to drop. Looking to stop these calls from occurring. Any help would be appreciated.