Asterisk block incoming call from specific country only - asterisk

Question

I am trying to make a dial plan to block incoming call coming from let say bangladesh where country code is 88
Here is my dial plan
exten => _X.,1,NoOp(${CALLERID(num)})
same => n,Set(regx=^(88)[0-9]$)
same => n,GotoIf($[${REGEX("${regx}" ${CALLERID(num)})} = 1]?blacklisted,s,1)
same => n,Dial(SIP/8.8.8.8/${EXTEN}
[blacklisted]
exten => s,1,Wait(9)
what i want to do is anything that comes from 88 should be sent to blacklist. At the moment if I test call with Caller ID 88 it works but if the call comes from 88XXXXXXX this does not work what can I do to make my dial plan block anything coming from 88XXXXXXXX to goto black list

Answer 1

Why do you use the complex REGEX function? Just do something like that:
exten => _X.,1,NoOp(CallerID is: ${CALLERID(num)})
exten => _X.,n,Set(number=${CALLERID(num)})
exten => _X.,n,ExecIf($[${number:2} = 88],Hangup())
exten => _X.,n,NoOp(Call is being continued)
This will save the callerid num into the "number" variable. Then it will check if the first 2 characters of the variable are equal to 88. If so, the call will be hung up. You can also use GoToIf instead of ExecIf if you want to send the blacklisted call to a specific context where you want to do something else with it.

Answer 2

Asterisk dialplan is regexp itself. Why you use other regexp?
exten => _X.,1,NoOp(${CALLERID(num)})
same => n,Gosub(cid-blacklist,${CALLERID(num)},1)
same => n,Dial(SIP/8.8.8.8/${EXTEN}
[cid_blacklist]
exten => _88.,1,Noop(bangladesh)
same => n,Wait(100)
; this works only when not found match in context.
include=> cid_blacklist_not_found
[cid_blacklist_not_found]
exten => _X.,1,Return;not found in cid blacklist