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Randy IT Tech
Randy IT Tech, Network Administrator
Category: Networking
Satisfied Customers: 9705
Experience:  Information Technology Specialist
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I recently purchased a Netgear N900 router, model

Customer Question

I recently purchased a Netgear N900 router, model WNDR45000v3. I changed my home phone to Vonage and when I receive calls the caller cannot hear me. Vonage thought it was my internet provider's firewall, but they said no. Now I wonder if the router has a firewall that is preventing the passage of voice.
Submitted: 1 year ago.
Category: Networking
Expert:  Randy IT Tech replied 1 year ago.

These issues are often due to your router's firewall (also known as NAT) blocking certain operations of the VoIP telephone adapter. Try the following solutions to resolve the issues. Please make changes one at a time and reboot your router and VoIP device each time to see if the problem is solved.

1.) Please check that you have Internet connectivity (try to view a few web sites) and check if your router/firewall settings have changed.

2.) IMPORTANT Upgrade the firmware (firmware is similar to software) on the router. Most VoIP firewall isues are resolved by router firmware upgrade. For detailed instructions consult your router's user guide or the manufacturer's web site.

3.) Some routers alter SIP packets with the default configurations which creates VoIP service problems. From your router’s web configuration page (usually under configuration / firewall / advanced settings);

- Disable Stateful Packet Inspection (SPI) if applicable.

- Disable SIP Application Layer Gateway (SIP ALG) if applicable.

4.) Try disabling your firewall (turn it off completely) briefly. Reboot your router and VoIP device and check if you can make/receive calls. If you can do so now then your problem was with your routers firewall configuration. You firewall is not allowing calls to your SIP phone. You can continue using your router as firewall disabled or if you want the firewall enabled on your router try following solutions.

5.) Enable the DMZ option on your router which will open the firewall for one specific host. To determine the IP address or host (your VoIP device) to enable DMZ for, you will need to login to your router and look at the devices connected to it. From there you can get the internal IP address or host information that it has assigned to your VoIP device. For detailed instructions consult your router's user guide, the manufacturer's web site.

6.) Disable DMZ and try forwarding only VoIP ports on the router to your VoIP device. The following ports are needed for VoIP communications from your VoIP device to the VoIPVoIP servers. Consult routers manual or call their technical support to forward these ports on your router/firewall:

(*) port 5000-5500 for UDP and TCP

(*) port 10000-20000 for UDP

Customer: replied 1 year ago.
I need to know how to update the firmware on my router.
Expert:  Randy IT Tech replied 1 year ago.


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