I've got a HFC NBN connection and the following setup lets me use both my BYO router as well as the VoIP phone. I've put in a network switch (cost under $20) between the NBN Box and the routers. The NBN Box is connected to the switch. The switch is connected to the WAN port of the BYO router, and the switch is connected to the WAN port of the TPG router. I haven't changed any settings in either router. They both have their normal IP addresses and both are running DHCP. The effect is that you're running two independent LANs. The BYO router runs my main network and my WiFi. The TPG modem runs the phone connection. I've switched off the WiFi on the TPG modem as I don't need another WiFi network in the house, but that is a personal choice. In fact, if you put the TPG modem in a different part of the house another WiFi network may be useful. You can connect other devices to the TPG router to access the internet as well as each other, but they won't be able to communicate with the devices connected to the LAN on the BYO router. Hope this helps.
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Hi, If you check the log file on the modems (TPG) the SIP registers to server 172.26.0.1:5060 Therefore the Registrar IP should be that one 172.26.0.1. The username and password may either be blank for both, the TPG username and password or something else. Hope that helps
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