Dropping incoming calls without a Callerid

Asterisk Asterisk Support
1

Hi,

Would it be possible to block incomming calls on a ZAP channel with no caller id and perhaps divert them to a message explaining we can only accept the call with a valid callerid?

Cheers

Chreeeeeeseh!!!.

2

From the wiki change to suit your needs

voip-info.org/wiki/view/Asterisk+cmd+GotoIf

; This example checks for blank caller ID or 800 numbers.
; Callers from 800 numbers (usually telemarketers) or those
; with no caller ID are asked to press 1 to speak with me.
exten => s,1,NoOp(${CALLERID}) ; log callerID string
; check for callerID. If none, make them hit 1.
exten => s,2,GotoIf($["${CALLERIDNUM}" = “”]?s|1000)
; If 800 number, make them hit 1.
exten => s,3,GotoIf($["${CALLERIDNUM:0:3}" = “877”]?s|1000)
exten => s,4,GotoIf($["${CALLERIDNUM:0:3}" = “800”]?s|1000)
; OK, we have valid caller ID and it’s not an 800 number.
; Let’s ring our phones now:
exten => s,5,Dial(SIP/604&SIP/602,25,tr)
exten => s,1000,Background(press1tospeaktome)

3

Yes. Gotoif() can be used and ${CALLERIDNUM} compared with ""
or ${LEN(${CALLERIDNUM})} > 3 number must be longer than 3 digit

4

Thanks :smiley:

5

why not just use PrivacyManager()? I had to make some customizations because a number of telemarketers have UNAVAILABLE or OUT OF AREA instead of blank. here is what i did:

;
; Special tweaks we do for incoming calls.  AAH doesn't allow invocation
; of privacy manager for PSTN calls, or invocation of zapateller, so we
; "roll our own" here.  Also, for inbound PSTN calls, wait 3 seconds in
; case it's a fax call (to allow nv_detect_background) to redirect the
; call to fax context if so.  Also, asterisk providers seem to send odd
; strings like 'asterisk' or 'UNKNOWN' when CID is blocked - check for
; that and null out both strings if so.  Telemarketers often seem to
; use UNAVAILABLE or OUT OF AREA, but sadly, there is sometimes trailing
; spaces, so trim those off.  Any legitimate caller will get a chance to
; provide his real CID via Privacy Manager
;

[custom-zaptel4]
exten => s,1,Answer
exten => s,n,Wait(3)
exten => s,n(blacklisted),LookupBlacklist(j)
exten => s,n,Set(foo=${CALLERID(name)})
exten => s,n,Set(foo=${CUT(foo, ,1)})
exten => s,n,GotoIf($["${foo}" = "UNKNOWN"]?fixup_cid)
exten => s,n,GotoIf($["${foo}" = "PRIVATE"]?fixup_cid)
exten => s,n,GotoIf($["${foo}" = "OUT OF AREA"]?fixup_cid)
exten => s,n,GotoIf($["${foo}" != "UNAVAILABLE"]?check_cid)
exten => s,n(fixup_cid),SetCallerID(,)
exten => s,n(check_cid),Zapateller(nocallerid)
exten => s,n(privacyfailure),PrivacyManager
exten => s,n,LookupCIDName
exten => s,n,Goto(timeconditions,3,1)
exten => s,privacyfailure+101,Congestion
exten => s,blacklisted+101,SetCallerID(,)
exten => s,n,Zapateller(nocallerid)
exten => s,n,Congestion

unfortunately, i can’t just check for UNAVAILABLE and such, because asterisk presents the string with trailing spaces, so i trim those off. if it’s any of the suspect names, i nuke the caller id and then invoke privacy manager, so they will be prompted to enter their number. note: real telemarketers will never get this far, since zapateller() will play the disconnect tone and their autodialer will hang up.

6

you could also try the PrivacyManager() application. If there is no caller id it will play a message and require them to manually dial in their caller id.

7

that is in fact what i do. my point was: many telemarketers do provide a canned CID like UNAVAILABLE, and privacy manager will not block those.