[asterisk-users] Checking blank CallerID in Dialplan

[Myles Wakeham]

I am trying to implement a change to our Dialplan that will thwart 
tele-spammers that are calling us with blanked out caller ID.

The caller IDs seem to vary between originating callers when they block 
caller ID.  I've seen the following:

"anonymous"
""

So I'm checking for these.  However recently one company seems to be 
bypassing this, so what I wanted to do was implement some logic that 
checks for actual numbers in the caller ID.

We have a couple of different SIP providers for incoming calls.  Some 
prefix numbers with a +  and others don't.  But I'm logging incoming 
calls that are getting through our tele-spam filter and it seems that 
they are blank, but I suspect they contain empty spaces which is why our 
matches don't work.

Does anyone have some sample DialPlan code that they are using to thwart 
incoming calls with no caller ID?  I was thinking of maybe converting 
the caller ID num to a numeric value and testing for 'not equal to 0' 
but that won't work with the + prefix.

All suggestions greatly appreciated.

Myles
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Myles Wakeham
Director of Engineering
Tech Solutions USA, Inc.
www.techsolusa.com
Phone +1-480-451-7440