Yes the call does fork to the mobile when the phone is not on DND.
What I want is that when there is an internal or external call to say extension 3010 that it calls their mobile as well. When the phone is not in DND this works perfectly, but as soon as you DND the phone it puts the call straight to the users mailbox and doesn't ring the mobile at all, If i then check the extension in the snomone pbx the extnesion is set to DND = off. This seems a little confisuing.