- Ensure Network Service is configured with default gateway
- Note IP address of PBX LAN and PBX DSP Card 1
- Media Relay - NAT - External IP Address set to Public IP
- Disable SIP ALG, SIP Transformations, FTP ALG and FTP Transformation, H.323 ALG and H.323 Transformations
- Ensure the PBX Public IP matches the inbound Public IP, otherwise add routing routes as required.
- Add Address Objects to Firewall for the PBX LAN and PBX DSP Card 1 addresses.
- Add Service Objects to Firewall as below:
- UDP16000-16511 (DSP1)
- Add NAT rules to Firewall as below:
- UDP16000-16511 → DSP Card 1
- UDP2727 → PBX LAN
- UDP9300 → PBX LAN
- Add firewall rules to allow above, restricted to IP address of client handsets using a new address group preferably.
- Using Public IP of PBX
Configuration→Slot→IP Phone Registration
- Set Remote Place → Phone Location to Remote (MRG)