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Talk Is Cheap by James E Gaskin

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Stumbling Blocks

Today, getting a software phone and making calls out to other users of the same service is a snap. Even calling out to traditional telephone users works well and costs little. But getting inbound calls from traditional telephone users still includes plenty of hassle.

Getting the Firewall Out of the Way

When using a router supplied by a broadband phone provider such as Vonage, many connection issues are handled for you. The router’s security configuration takes into account the attached broadband phones and initializes the firewall security settings properly to allow full phone access.

Using a software phone when you have a typical broadband router with even minimal security makes things more complicated. The problem comes with the way your router hides your internal devices (computers) from hackers on the Internet: the router masks your device’s actual IP address. When a request from your computer goes through the router, the Network Address Translation (NAT) portion of the router’s security software attaches its own address along with a specific port number.

When return packets (say the web page you asked to view) get back to the router, they include the specific port number given the outgoing packets by the router. The router then connects the outside packets to your device. Outsiders can’t see through your router to your internal devices because internal device addresses never go past the router.

Note

Do the NAT Thing

In plain terms, every machine on the outside world ...

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