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I am using rackspace cloud hosting. I have 2 servers behind a load balancer. Each server has an external IP and an internal IP. I want to setup a sync job that uses SSH to transfer files. I made an rsa key, and I can successfully SSH from server A into server B, using the external IP of server B, without being prompted for a password. If I try to do the same but use the internal IP, it prompts me for a password. I want to be able to use the key instead of the password. Why is this? Is there something special I have to do during key generation so it works for both IPs?

Any help is appreciated.

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It would help if you posted the commands you are using. You can supply ssh with a path to your keyfile: ssh -i ~/.ssh/id_rsa $IP – Baarn Dec 14 '12 at 20:51
My key file is in the ~/.ssh/authorized_keys so I dont have to specify the key file. So when doing this ssh username@externalIP it logs right in, when doing this ssh username@internalIP it prompts for a password. – Ian Dec 14 '12 at 20:58
authorized_keys are located on the server, you need to specify the private key you are using on the client. You can also create a config file in your .ssh folder. Check man ssh_config for syntax. – Baarn Dec 14 '12 at 21:07

Need to add to the ~/.ssh/config file

Host internalIP
        IdentityFile ~/path/to/key
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