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Support Centre Troubleshooting Articles Known Incompatible Routers

Known Incompatible Routers

This page lists any modems/routers that have been identified as incompatible with our services.


While most brands and models of modem/routers work without issue on our service, occasionally a router can present errors in the way they handle voice calls that we're unable to correct.

Due to the varied nature of devices available on the market, this list is updated periodically as new devices are identified. It's also important to note that these routers, since being added to this list, may have received firmware updates that corrects the issue. If a firmware update has been shown to correct the issue in majority of deployments, this list will be updated with the specific firmware requirements.


If you're experiencing issues with your modem/router, and it's not listed below, you may have SIP ALG enabled. For information on SIP ALG, along with guides to disable it on several common routers, please see SIP ALG


DeviceImportant NotesPresented Issue
Telstra Smart Modem 2nd/3rd GenOnly applies when using 4G backup

When using the built in 4G backup facility, if for example your NBN is unavailable, phones may not be able to connect. Try restarting the router or contact our team to change the 4g profile.

When your connection switches from 4G back to your NBN, your phones may not reconnect correctly. Restarting the router should correct this.

SagemCom F@STOptus suppliedThis router has an inbuilt SIP ALG that is not configurable in the web interface. This may cause phones to be unable to connect, continue ringing, or present one-way or no audio on calls.
Draytek RoutersVarious models
  1. When multiple phones are connected through the Draytek, a single phone may not work. The issue may move around phones. There's no known workaround at this time.
  2. Phones may continue to ring after answer, or calls may be routed to the wrong phone. Set individual SIP listening ports for each phone to work around the problem.
Huawei B818Optus suppliedThis router may only allow a single handset to connect. Any additional handsets will fail to connect correctly.
Netcomm NL1902 + NL Series + NF20 (Possibly others in the NF series)May be a different brand (eg Vodafone NL1902)SIP ALG must be enabled for phones to connect correctly.
Ubiquiti EdgerouterAffected Models: ERLite-3, ERPoE-5, ER-8, ERPro-8, EP-R8, ER-4, ER-6P, ER-12 , ER-12P, ER-8-XGHardware NAT implementation may cause inbound calls to fail intermittently. Enabling quality of service features works around the issue.
Belong 4353Belong SuppliedThis router may prevent phones from registering on the most recent firmwares. There is no known workaround at this time.
Sagemcom 4315Belong SuppliedThis router may prevent phones from registering on the most recent firmwares. There is no known workaround at this time.
SophosFirmware 18.5/19With SIP ALG enabled only a single phone will register. Firmware upgrades can re-enable SIP ALG. See Disabling SIP ALG - Sophos XG
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