Transfer only to internal numbers


I use Asterisk 1.8.X.

At this time, if I receive a call from the outside, I can transfer it back to an outside line.
How to restrict the transfer only to internal numbers.

I would like to put the blockade for “Attended Transfer” and “Blind Transfer”

Best regards,


How are you requesting the transfers? In particular, SIP attended transfers are always done in the same context as SIP outgoing calls from the same phone, as the PABX does not know they will become transfers. Transfers that are done at the SIP user interface level as blind transfers may actually be handled as attended transfers by the phone.

For features transfers, and possibly for SIP blind transfers handled by the phone as such, there is a channel variable that you can use to override the context used for them. Look in any of the lists of built-in channel variables to work out the exact name. This might not be necessary in those cases, as I think that the default context is that of the incoming call.

I make a transfer option from phone Cisco.
I’m looking for some simple examples of how to make the block.

I doubt that there is an eay way of achieving this if it dosen’t happen naturally.

If you haven’t tried setting the channel variable try doing so.

Otherwise, given your limited answers to my original question, I suspect that the following may be too technical for you, however, if the call is being done as a SIP attended transfer, you could try adding code to the dial plan to detect how many calls are in progress on the phone and restrict the context if there is more than one.