Whether the FVS124g gigabit VPN router is a good piece of equipment or not I leave for another day. But, if you want it to work with Vonage you must do the following (thanks to Netgear Enterprise post moderator endurorider – used with permission)
Join Date: Nov 2006
Re: Peaceful Coexistence of FVS124G and Vonage Using Linksys PAP2
You need to turn off SIP ALG on the FVS124G.
Disabling SIP through CLI on FVS124G to allow VoIP traffic to pass
Telnet to the LAN interface of the router. You must be connected locally to one of the routers LAN ports.
Enter your Username and Password. This is the same as if you were logging into the webGUI.
Type Cli using a capital C.
You should now be in the CLI of the router. Type config/algs.
There are 6 different protocols you need to disable.
Use the command disable
Check to make sure the 6 protocols have been disabled by using the show command.
Save your work by typing save command. When you hit Enter, there may be a slight delay while the router is saving.
Finally, type exit and then logout and youre done!