Level 2: Rookie


My AV registered an internal port scan suggesting the Smart Modem has been hacked or wasn't up to the task of protecting my network.  So I have purchased a WatchGuard T20 firewall which I wish to put between the NBN HFC modem and the rest of the network. Problem is the telephone will cease to work.

Has anyone put in an ATA (Analogue Telephone Adapter) between the NBN HCF and the firewall/modem to break out the phone separately and had the phone still working?

Do I still need to have the Smart Modem connected to validate the connection with account details?

I did put the T20 firewall after the SmartModem and sure enough, it detected some nasties, so I know the modem is not that strong. 

Can I do away with the Smart Modem altogether?

If you have a solution using an ATA, what brand as I have read that they only have a 20Mb bandwidth and I would like something up to 100Mb?  Not that this matters that much as the link is painfully slow despite the 45Mb promise. Yes, slower than the old ADSL or a dial up modem. Watching simple U-Tube is cringe worthy.

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Level 2: Rookie



I have configured my Watchguard T20 to pass though the SIP-ALG voice calls and the T20 now sits between the NBN HFC NTU and the NextGen2 modem.

The T20 comes with a default SIP-ALG client which can be easily added to the Firewall policies.  The Next step is the SNAT that has to be enabled to go from:

NBN HFC NTU = (101.nnn.nnn.nnn)in-NG2-out = Int I/F + Detect Phone. to:

NBN HFC NTU = (101.nnn.nnn.nnn)in-T20-out ( Set I/F to Optional = ( = Int I/F + Detect Phone.

Works like a charm.

The SNAT configuration is:

* IP Address or Interface = External
* Choose Type = Internal IP address
* Host =
* Set Source IP Address (Ticked Yes)
* Set Internal Port (Not Ticked)

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