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cannot rsh to linux using public key

Posted on 2012-04-04
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Last Modified: 2012-06-27
I'm reposting this because apparently my problem is not solved.

I have 2 linux computers. I am trying to ssh from one to the other w/o passwords. I can ssh from computer A to computer C, but not from A to B. I can't see where the difference is. On computer A,  I ran ssh-keygen which created ~/.ssh/id_rsa.pub.

I copied the contents of that id_rsa.pub file. Then, logged into computer B and appended the contents of A's id_rsa.pub to B's ~/.ssh/authorized_keys. I did the same with computer C.

When ssh'ing from A to C I get logged in, no password prompt. When ssh'ing from A to B it prompts me for a password. What am I doing wrong?
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Question by:jmarkfoley
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Expert Comment

by:torakeshb
ID: 37809660
There is no way.  I think you could have copied the wrong key file to server B..

"When ssh'ing from A to B it prompts me for a password." --> Are you able to get it when you give the password.
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Expert Comment

by:gnemi
ID: 37809696
The public key goes to the server receiving the connection. The private key stays on the client.

The public key needs to be pasted into authorized_keys on the server. Private keys should be in the .ssh folder of the user you are connecting with.
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Accepted Solution

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larsrohr earned 400 total points
ID: 37809780
So far, it seems you've taken the right steps.
A common issue is that of file permissions.  ssh won't honor your authorized_keys file if permissions on it or on ~/.ssh are too loose.  So a good place to start is with:
 chmod 700 ~/.ssh
 chmod 600 ~/.ssh/authorized_keys

It could also be that the sshd_config on B is different, not allowing public key authorization.  This isn't very likely, I'd say, but it may be worth comparing sshd_config on B versus C (often this is at /etc/ssh/sshd_config).

For a bit more clarity on the problem, assuming the above doesn't help, please try ssh'ing verbosely.  The output may be illuminating, if you can share it here.
 ssh -vvv username@Bmachine
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Assisted Solution

by:bandris
bandris earned 100 total points
ID: 37810737
The most likely problem is the ownership or mode on
1. authorized_keys file or
2. .ssh directory

If you use ssh-copy-id to put you public key on remote computers you will not mess up the rights accidentally.
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Author Closing Comment

by:jmarkfoley
ID: 37812275
Changing the permissions on the authorized_keys worked! I can't believe that didn't occur to me, but it was late. Bandris, great tip on the ssh-copy-id program. I didn't even know it existed.
Thanks
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