I have a VoIP system which resides behind an ASA5505. I need to configure port forwarding of ports 10000 to 20000 to my VoIP system. The only way I can achieve this is by creating a static NAT of all IP traffic then restricting the ports by an Access Rule. It is impossible to create a static NAT rule for every port. Is there an alternate way of achieving this result? I am asking so because I cannot publish a separate service to a different internal IP which is not the VoIP system.