asterisk users - Aug 2004 - limit the length of extensions

How do I limit the length of an extension? In my test IVR/Automated 
Attendant (whatever it's called), at the beginning it plays "if you
know
your parties 3 digit extension, you may enter it now) and then it gives 
a list of options. If the caller puts the 3 digit extension, it goes 
through fine, if they press 1, or 2 it goes to the selected menu option, 
but if they dial 91235551212 it dials that phone number. Which of 
course, is a big security risk.

Is there a way to limit the length of an extension for an incoming call? 
My only solution right now is to duplicate ever single extension (about 
50 of them) in a seperate context, one that does not have the _9. 
extension in it, and then make the call in menu have access to that 
context.  However, if I put a limit in the entire context of 3 digits, 
then my coworkers who's phones are in that context can only dial each 
other, not 9 and an outside number. So it has to be an incoming limit or 
something.

Another possibly creative solution would be to "SetGroup(outsidecaller) 
on the incoming line" and then just before my outbound extension put 
"SetGroup(outsidecaller) and then a CheckGroup(2)" or something like 
that.  I'd have to put another "SetGroup" in the outbound
extension
because there's no way to specify the group with the checkgroup command, 
it gets it from the setgroup statement.

Any help would be appreciated.

Thanks,
Deon



[incoming]
exten => 9543340726,1,GotoIf($[${CALLERIDNAME} = anonymous]?2:4)
exten => 9543340726,2,setcidname(Blocked)
exten => 9543340726,3,setcidnum(0000000000)
exten => 9543340726,4,Goto(companyname,beginmenu,1)

[companyname]   ; All the phones, including outbound extensions are in 
this context
exten => beginmenu,1,SetVar(CALLEDNAME=CompanyName)
exten => beginmenu,2,Wait,1
exten => beginmenu,3,Background(company-main)
exten => beginmenu,4,Background(ifyouknow)
exten => beginmenu,5,Goto(company_mainmenu,s,1)
exten => 
_9NXXNXXXXXX,1,Dial(IAX2/company-asterisk@outbound-asterisk/${EXTEN:1})
exten => 502,1,Dial(SIP/whatever1&SIP/whatever2|30|m)
...

[company_mainmenu]
exten => s,1,Background(company-nav1)
exten => 1,1,Goto(company_sales,s,1) ; Sales
exten => 2,1,Goto(companyname,502,1) ; Accounting
exten => 3,1,Goto(companyname,508,1) ; Customer Care
exten => 4,1,Goto(companyname,507,1) ; Technical Support
exten => 5,1,Goto(companyname,202,1) ; Human Resources
exten => 6,1,Goto(companyname,202,1) ; Provisioning
exten => 7,1,Goto(companyname,214,1) ; Marketing
exten => 0,1,Goto(companyname,210,1) ; Operator

You limit them by context.  You put your outbound dialing patterns in a
context that inbound callers cann't access.

Lyle

----- Original Message ----- 
From: "Deon Rodden" <drodden@webunited.net>
To: <asterisk-users@lists.digium.com>
Sent: Tuesday, August 31, 2004 9:05 AM
Subject: [Asterisk-Users] limit the length of extensions

> How do I limit the length of an extension? In my test IVR/Automated
> Attendant (whatever it's called), at the beginning it plays "if
you know
> your parties 3 digit extension, you may enter it now) and then it gives
> a list of options. If the caller puts the 3 digit extension, it goes
> through fine, if they press 1, or 2 it goes to the selected menu option,
> but if they dial 91235551212 it dials that phone number. Which of
> course, is a big security risk.
>
> Is there a way to limit the length of an extension for an incoming call?
> My only solution right now is to duplicate ever single extension (about
> 50 of them) in a seperate context, one that does not have the _9.
> extension in it, and then make the call in menu have access to that
> context.  However, if I put a limit in the entire context of 3 digits,
> then my coworkers who's phones are in that context can only dial each
> other, not 9 and an outside number. So it has to be an incoming limit or
> something.
>
> Another possibly creative solution would be to
"SetGroup(outsidecaller)
> on the incoming line" and then just before my outbound extension put
> "SetGroup(outsidecaller) and then a CheckGroup(2)" or something
like
> that.  I'd have to put another "SetGroup" in the outbound
extension
> because there's no way to specify the group with the checkgroup
command,
> it gets it from the setgroup statement.
>
> Any help would be appreciated.
>
> Thanks,
> Deon
>
>
>
> [incoming]
> exten => 9543340726,1,GotoIf($[${CALLERIDNAME} = anonymous]?2:4)
> exten => 9543340726,2,setcidname(Blocked)
> exten => 9543340726,3,setcidnum(0000000000)
> exten => 9543340726,4,Goto(companyname,beginmenu,1)
>
> [companyname]   ; All the phones, including outbound extensions are in
> this context
> exten => beginmenu,1,SetVar(CALLEDNAME=CompanyName)
> exten => beginmenu,2,Wait,1
> exten => beginmenu,3,Background(company-main)
> exten => beginmenu,4,Background(ifyouknow)
> exten => beginmenu,5,Goto(company_mainmenu,s,1)
> exten =>
> _9NXXNXXXXXX,1,Dial(IAX2/company-asterisk@outbound-asterisk/${EXTEN:1})
> exten => 502,1,Dial(SIP/whatever1&SIP/whatever2|30|m)
> ...
>
> [company_mainmenu]
> exten => s,1,Background(company-nav1)
> exten => 1,1,Goto(company_sales,s,1) ; Sales
> exten => 2,1,Goto(companyname,502,1) ; Accounting
> exten => 3,1,Goto(companyname,508,1) ; Customer Care
> exten => 4,1,Goto(companyname,507,1) ; Technical Support
> exten => 5,1,Goto(companyname,202,1) ; Human Resources
> exten => 6,1,Goto(companyname,202,1) ; Provisioning
> exten => 7,1,Goto(companyname,214,1) ; Marketing
> exten => 0,1,Goto(companyname,210,1) ; Operator
>
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On 07:05 AM 8/31/2004, Deon Rodden wrote:
 >How do I limit the length of an extension? In my test IVR/Automated
 >Attendant (whatever it's called), at the beginning it plays "if
you know
 >your parties 3 digit extension, you may enter it now) and then it gives
 >a list of options. If the caller puts the 3 digit extension, it goes
 >through fine, if they press 1, or 2 it goes to the selected menu option,
 >but if they dial 91235551212 it dials that phone number. Which of
 >course, is a big security risk.
 >
 >Is there a way to limit the length of an extension for an incoming call?
 >My only solution right now is to duplicate ever single extension (about
 >50 of them) in a seperate context, one that does not have the _9.
 >extension in it, and then make the call in menu have access to that
 >context.  However, if I put a limit in the entire context of 3 digits,
 >then my coworkers who's phones are in that context can only dial each
 >other, not 9 and an outside number. So it has to be an incoming limit or
 >something.

It sounds like you need to break your dialplan into more focused 
contexts.  Create a context for access to an outside line (you can even 
break this down into access for toll-free, long distance, local, 
local-toll, international, '976' numbers, etc.  Create contexts for each
set of company extensions, create contexts for all the ivr systems 
separately, so only the options you want are available.  Then use include 
statements to only include the access you want for each context.  When I 
set systems up like this I also include 'anti' contexts.  For example,
if I
include a local context that allows 7, 10, or 11 digit dialing, I also 
include a context !local that plays back an unauthorized message if someone 
dials a matching number.  This way you can not only catch access to 
unauthorized features by implicitly denying access, but you provide the 
user with a reason why they are not able to place the call they just dialed.

-Chris