I have just installed 12.5 for a new client. Default install on server 2012. It has installed to IIS and has configured itself with ports 5000-1. All working ok internally with the exception of Iphone clients do not get status/presence. Externally Windows clients register ok, calls work ok but again presence/status does not work. Firewall is configured with open ports for 5000-5001 plus all other standard 3CX ports and all call features work ok. help!