In a Small Business, Cisco Call Manager Express (CME) provides IP PBX functionality and Cisco Unity Express (CUE) provides unified messaging. This article explains how to create a non dialable extension number for the setting of Message Waiting Indicators to stop the accidential or malicious setting of MWI.
Both CUE and CME have to be configured with the same numbers to turn on and off Message Waiting Indictor (MWI). Thus when a new voice mail is left for a user, CUE will dial a preconfigured number to tell CME to set the MWI light on a phone. CUE will dial another preconfigured number to turn the light off once a user has listened or deleted their messages.
If a dialable extension number is used for MWI, it is possible for phone users to either accidentally or maliciously set MWI on or off on other users' phones.
If for instance the MWI On value is set to the following:
Number 9000 …
It is possible for anyone to dial 9000 followed by a four digit extension number. Thus for instance if 90001000 was dialed, the MWI on extension 1000 would be turned on.
To stop this behavior, the following could be configured:
Number B9000 ….
Number B9001 ….
As the number B9000 and B9001 cannot be dialled from a standard Cisco telephone, this will stop users from setting MWI. Numbers AD are valid numbers on certain special phones.
To set up CUE, do the following on the CUE aim / module:
Ccn application ciscomwiapplication
Parameter "strMWI_OFF_DN" "B9001"
Parameter "strMWI_ON_DN" "B9000"
This will stop users from maliciously setting on / off MWI.