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Possible Duplicate:
How to use DNS to redirect domain to specific port on my server

Right now I have a DNS CNAME record that makes ftp.angryoctopus.net an alias for the actual FTP URL domain, which is angryoctopus.net:65021

The goal is that a client should be able to type ftp://ftp.angryoctopus.net/ in their browser's address bar, and be directed to Angry Octopus's FTP site on my server - which is hosted at port 65021.

Of course the hostname won't resolve.

Is it possible to accomplish this type of alias somehow, or am I just beating a dead horse? This reminds me of DynDNS, which I used a few years ago for something-or-other. How does DynDNS spoof ports like that, and can I immitate it to make this work?

I should add that this is running on a stand-alone server, hosting multiple FTP sites. I am using Windows Server 2003 w/SP2 for DNS and IIS 6.0

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Giffyguy
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2 Answers2

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There's no way to do it for all protocols. The only reason it can be done for HTTP is because the Location response header can be used to direct the HTTP client to an arbitrary URL. Most protocols have no such redirection capability, and instead something like SNAT must be used.

Ignacio Vazquez-Abrams
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DNS is not the way to do this .. DNS relates names to IP addresses. You use DNS to tell the internet that angryoctopus.net is on 1.2.3.4, and that ftp.angryoctopus.net is at the same place at angryoctopus.net. DNS doesn't care about ports.

This can be done with Network Address Translation (NAT). Put a firewall between the internet and the ftp server which can translate the standard ftp traffic to the ports you desire. The mechanics of how it is done differ depending on the firewall. If you have a firewall, it can very likely do this. If not, there are hundreds of good choices .. I like Astaro.

tomjedrz
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  • I have a Linksys RV042 dual-wan firewall, which is cheap but still business-quality. If this is a firewall feature, then I'm fairly ceartain my current firewall will support it. Lemme look through the adminstration interface and see what I can dig up. – Giffyguy May 15 '10 at 17:48