Level 1: Cadet

Cisco voip phone 7940 not working with Telstra Gateway Max c6300

One of my employees will be working from home and he has just been upgraded to NBN using a Telstra Gateway Max C6300 modem. The Cisco 7940 is connected via the lan port and

configured with the voip providers details. My employee can receive calls and hear the caller perfectly but they cannot hear him. Zoiper softphone works. We have tried the

following with no success


Port forwards using both a fixed and not fixed ip for the voip phone

        Rule 1:
        Name : SIP
        Type : UDP
        Start Port : 5060
        End Port : 5061
        IP Address: "this will be the IP Address of the Voip device connected directly to the router. If you know the IP address simple select it from the drop down left.

        Rule 2:
        Name: RTP
        Type: UDP
        Start Port : 10000
        End Port : 20000
        To set up a default DMZ server:
        > 1. On your computer, launch an Internet browser such as Mozilla
        > Firefox or Microsoft
        > Internet Explorer.
        > 2. In the address field of your browser, enter http://routerlogin.net
        > [http://routerlogin.net].
        > You are prompted to enter a user name and password.
        > 3. Type admin for the user name and type your password.
        > If you did not yet personalize your password, type password for the
        > password.
        > 4. Click the OK button.
        > The BASIC Home screen displays.
        > 5. Select ADVANCED > Setup > WAN Setup.
        > The WAN Setup screen displays.
        > 6. Select the Default DMZ Server check box.
        > 7. Type the IP address for the DMZ server.
        > 8. Click the Apply button.
        > Your settings are saved and the cable data gateway might restart.
        Neither of these have worked. This phone works with other modems perfectly. Also Zoiper softphone client works as well. Any suggestions as this is getting very


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