Black and white lists

1. Go to System → System file custmization.

System file customization menu

2. Open the extensions.conf configuration file for editing.

extensions.conf

3. Set the "Add to end of file" mode and paste the following code:

[add-trim-prefix-clid-custom]
exten => _X!,1,NoOp(...)
    ; Blacklist of numbers. The call will be completed.. 
    same => n,ExecIf($["${CALLERID(num)}" == "491771789427"]?Hangup())
    same => n,ExecIf($["${CALLERID(num)}" == "4915735987904"]?Hangup())
    same => n,ExecIf($["${CALLERID(num)}" == "4915735996685"]?Hangup())
    same => n,return

Code for extensions.conf

The whitelist of numbers sometimes needs to be described for specific providers:

[Provider-ID-incoming-custom]
exten => _X!,1,NoOp(...)
    ; Whitelist of numbers. 
    same => n,ExecIf($["${CALLERID(num)}" == "491771789427"]?return)
    same => n,ExecIf($["${CALLERID(num)}" == "4915735996685"]?return)
    same => n,ExecIf($["${CALLERID(num)}" == "4915735987904"]?return)
    same => n,Hangup()

• PROVIDER-ID - the value that you can find in the address bar at the time of provider configuration

Provider ID