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Why NAT Traversal Matters To You

Michael GetzingerBy Michael Getzinger

Have you ever wanted to connect to your home machine from work -- or vice versa -- but were unable to do so because you were behind a Linksys, NetGear, or Apple router?

What about using Skype to make free phone calls over the Internet from your home, or from a public WiFi hotspot in a coffee shop, or from a hotel?

Have you ever wanted to help someone by remotely controlling their computer -- or be helped yourself -- but couldn't because of a firewall?

Without the power of "NAT traversal", none these things would be possible.

Due to a quiet revolution in the way many modern programs communicate, you now have the power to communicate with machines over almost any type of network.

You might not understand this paragraph, but that's OK: "NAT" (Network Address Translation) allows you to share your public IP address with multiple private IP addresses.

Whether using a home router/firewall or inside a large corporate network, Network Address Translation is being done to shuttle internal network traffic to/from the Internet, i.e., internal IP addresses are "translated" to external addresses, and vice-versa.

But what if you want to remotely control your home or work PC?

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Traditionally you'd have to open a port in your home firewall/router. For example, if you were using "pcAnywhere", you'd have to open a specific port in order to be able to connect from outside your home network. To connect to your work machine, you'd have to ask IT to open a port for you in the company firewall (good luck).

NAT Traversal allows you to connect to machines without opening ports in routers or firewalls.

Several programs such as Skype,, Hamachi and others now simply "work": you merely install a program at home and at work and they can communicate automatically.

Of course this also raises potential security issues for businesses (and their IT departments): perhaps they don't want users connecting into their network by essentially bypassing their firewalls without their knowledge. As an IT professional myself, I certainly understand this concern!

For a more in depth discussion, listen to the Podcast below:

Episode #42 of "Security Now!: NAT Traversal"

About the Author:
I created to help cut through the glut of technical information by providing easy to understand articles on the best free software available. I'll be including reviews and step-by-step tutorials on configuring and using the best free software tools...

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