As of LCOS version 9.20, it is possible to prevent the processing of SIP messages from unknown VoIP servers.
- Allow SIP messages only from registrar
-
Enable this mode if the device should accept incoming SIP messages only from the registered IP address.Note: Please bear in mind that a high degree of compatibility is only assured if this feature is disabled. Incoming calls are not switched to internal subscribers if the VoIP provider signals calls that come from servers/IP addresses that do not match the registrar.