SIP in higher education

[Christian Schlatter <>]

Duane wrote:
> Jeremy George wrote:
> >   Do not call lists are indeed effective on the PSTN.  Being on them
> > has saved me hours of irritation.  However, such a mechanism may not be
> > as effective for VoIP.
>
> The point my friend was getting across is the DNC lists could very 
> easily be as useful for preventing VoIP spam because you are taking away 
> financial incentive or at the very least increasing the cost of doing 
> business to the point it becomes undesirable.

An interesting approach to prevent machine generated voice spam is to 
let an IVR challenge unknown callers with some simple question like 
'enter a number between 5 and 15'. E.g. sipera has implemented such a 
solution in their VoIP security platform, they call it "VoIP Turing 
Test". This method could be combined with secure caller-ID and 
white-listing so that the same caller has to do the test only once.

Of course the question remains if people would accept such an intrusive 
anti-spam solution.

Christian

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