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If I use Dynamic DNS such as the free service at, do I still need to set up static IP and do port forward ?

I have a DSL, most likely with dynamic IP address, and I run a Java servlet to get Paypal IPN messages on my notebook, in order for the messages to reach my notebook, I :

[1] set up static IP and 
[2] did port forwarding.

But I found each time the PC re-starts, it has a different external IP, so I was suggested to

[3] get Dynamic DNS service 

like the free one mentioned above, but now I'm a bit confused, if I have step [3], do I still need to do [1] and [2], isn't step [3] supposed to do [1] and [2] for me ? But since I've already done [1],[2], now I wonder if they would cause trouble for step [3], do I need to undo them ? Or do I need all of them together ?

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up vote 1 down vote accepted

If you are going through a router, you need to set up a static internal IP address for your computer and forward to that from your router (which can have a non-static external IP). If your computer is connected directly to the internet, you do not need to set up port forwarding.

I might also add that most routers have integrated support for dyndns clients, you just need to enter your login/password for your dyndns account somewhere in your router's web interface and it will update the dyndns server with its new IP address whenever that changes.

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Woo, thanks for that info, I use AT&T DSL, with a wireless 2Wire router, where on that web interface can I set up dyndns ? – Frank Mar 30 '10 at 18:00
Unfortunately, it does not seem that that router has support for integrated dnydns, so you'll have to just run the client on your PC. You can still look around for it if you want; on my linksys routers, it was under Setup > DDNS. – marcusw Mar 30 '10 at 18:21

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