Devices involved on this setup are the following:
- Modem is Draytek Vigor 2830n-plus connected to NBN Connection box UNI-D1; DHCP Server is disabled
- VoIP Gateway is Telstra Netgear 7610 connected to Draytek's LAN port, WAN port of the Netgear is unused; FXS1 and FXS2 are in used connected to MDF; DHCP Server is disabled
- Analog Telephone Adaptor Cisco SPA122 for the 3rd phone line
- Windows SBS 2008 which is the DHCP Server (option 66 is enabled)
Draytek Vigor2830n-plus WAN2 is configured using Static or Dynamic IP, not PPPoE so no ISP username and password needed to be configured to the modem.
Basically, the objective is to have the UNI-D1 connected to Draytek WAN/Gigabit port, then just connect Telstra 7610 LAN port to Draytek LAN port. Draytek is used as the modem because the Netgear 7610 VPN functionality is limited.