Offnet to Offnet calls are blocked using the service paramter "Block Offnet to Offnet transfer" so that transfers cannot be done from an ip phone, if the source and destination are pstn numbers. This works just fine. The phone do see a message on the LCD display "External Transfer Restricted" when they try to perform a transfer. All my gateways and route patterns have a Call classification of Offnet.
We are having an issue with pstn user calling an ip phone and the ip phone transfer the call to voicemailbox of a user. A CTI Routepoint *[1-8]XXX is setup which is call-forwarded to voicemail. This CTI route point is used to direct transfer to voicemail.
Here are the two scenarios that we have tested so far.
Case a: Internal call: Ip phone user a calls ip phone user b and tells her to transfer call to user'c (2781) voicemail, ip phone user b hits transfer softkey, dial * 2781 + transfer soft key and the transfer completes fine.
Case b: External call: Pstn user calls from cell phone to user b and tells her to transfer to user c's (2781) voicemail, ip phone user b hits transfer softkey, dial *2781 and when you hit transfer soft key, you get the message "External transfer restricted"
Why would Callmanager treat a call transfer to a CTI Route point (*[1-8]XXX) as an offnet call and block the transfer ? Note that CTI route points dont have an explicit call classification. So i would believe it should consider it as Onnet and not Offnet.