If  you  wish to forward DID purchased from us  to your Asterisk server through IAX .Kindly Choose Forwarding Destination of number  to " Your Own SIP Server" , Select " IAX"  (you canalso choose to  forward Via SIP ).  In "Host" enter IP Address of your Asterisk Server. In Details  Enter  Extension number to which DID  should be forwarded to

Here is how your IAX config file(s) should look ( Sample Configuration ).

 
iax.conf:
[virtualnumber-iax-1]
type=user
permit=46.19.209.42
context=from-virtualnumber


[virtualnumber-iax-2]
type=user
permit=46.19.210.42
context=from-virtualnumber