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Why is it needed? can't I just give an address:port and just "connect"?

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up vote 13 down vote accepted

The TCP/IP network stack in the Linux kernel only provides a means for data transport: you need a program that listens to the incoming data, processes that, and sends output data back. Such programs are usually called "servers" or "daemons"; that's why you need to run the "OpenSSH server" in order to receive SSH connections on your machine.

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The ssh connections to your computer are handled by an ssh server. If you do not have a server running then the connection request just gets ignored. Similarly: if you want to check a web page then the computer you are connecting to has to run an http server. In a default Ubuntu installation neither of these services are installed.

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good to learn something thats a bit different than the topic ;) – theTuxRacer Oct 24 '10 at 13:32

for more information about SSH protocols read this page :

Open-Ssh Web Page and help ubuntu

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OpenSSH server is not needed, but as Riccardo explains you will need some SSH server to accept the ssh connection and do something useful with it. And if you don't have a good reason to use something else, using OpenSSH is a good idea (it's the best known & most used SSH server, and thus well-tested).

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On a side note. If you are just looking to setup something like a little test server, then you can use a program called netcat. It is available in the software center / synaptic, or can be downloaded at:

With this tool you can create a fake server. Read some of the examples here

Keep in mind it isn't encrypted like SSH, this would just be for testing, I know it's a little off topic but figured it's useful information.

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