[Asterisk-Users] Preventing long-distance call forwarding

[Anthony Rodgers]

Well, I kinda answered this myself, and I'll post how I did it in case 
a) it might cause other problems and 2) anyone else finds it useful.

To recap, a Polycom phone will let you enter anything as a call 
diversion number - this is obviously a problem in that someone can 
forward their phone to Australia, go home and phone their extension to 
make the call to Australia for free. There doesn't seem to be anyway to 
configure the phone to restrict call diversion numbers.

Here's what happens:

     -- Called 2471
     -- Got SIP response 302 "Moved Temporarily" back from 172.16.16.100
     -- Now forwarding SIP/2293-2461 to 'Local/6045551212 at long-distance' 
(thanks to SIP/2471-d428)

The context is set from the called phone which, in the ordinary course 
of events, is allowed to make long-distance calls. For diverted calls, 
what I have done is this:

exten => s,1,GotoIf($[$["${CHANNEL:0:5}" = "Local"] & 
$[$["${MACRO_CONTEXT}" = "long-distance"] | $["${MACRO_CONTEXT}" = 
"international"]]]?:3)
exten => s,2,Goto(internal,${ARG2},1)
exten => s,3,...... rest of dialplan

This basically moves the call into a context from which only local 
calls are allowed, based on the channel starting with 'Local/'.

Does anyone see any glaring problems with this?

On Nov 24, 2005, at 4:04 PM, Anthony Rodgers wrote:

> Hi there,
>
> We have PolyCom IP501s in a context that allows long-distance dialing,
> but we want to prevent those same phones from being forwarded to
> long-distance numbers using the softkey on the phone (without disabling
> the key itself).
>
> Does anyone have any PolyCom/dialplan tricks to accomplish this? Even a
> way to reliably detect a call-forward in the dialplan would help....
>
> TIA.
>
> Regards,
> -- 
> Anthony Rodgers
> Business Systems Analyst
> District of North Vancouver
> Web: http://www.dnv.org
> RSS Feed: http://www.dnv.org/rss.asp
>
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