UNIX for Dummies Questions & Answers

We rebooted one our servers, call it server A, and now it cannot ssh into another machine, call it server B. We have the server A's ssh signature in server B's authorized key. I tried to manually generate the a new key using ssh-keygen command but the key looks nothing like the old key:

It has the--------------BEGIN KEY and ----------END KEY lines. So I copy everything including these two lines into the authorized key file and nothing happens.

I am stumped and would appreciate some assistance.

You dont have to have authorized keys to ssh into a server, that only if you want to not have to enter a password.

If you cannot ssh into a server at all, its probabally because sshd is not running.

I was not clear. I can ssh into the machine but it asks for a password DESPITE having the key in the authorized_key file!

I would assume you did the reboot because of some upgrades? it probabally upgraded openssh or something that would have generated a new key. Which is why it no longer matches. You just need to generate new keys and add them to known_hosts like you did the first time. You cant generate a new key and have it match the previous, that would not be a good thing.

Yeah I tried that but it still does not work! The only thing I can say is that in the machine I want to ssh into, it has the id_dsa.pub files for the machines that are allowedt to ssh into it without password. I doubt I have to do this but I felt like pointing it out to give all the information necessary. Any ideas? It seems like a simple cut and paste job....

I tried putting the public key for my own desktop into the Server B's authorized_key file and it worked! It just does not seem to work for Server A! Has anyone seen this type of problem before?

I do notice that Server A has:

openssh-4.3p2-24.el5
openssh-clients-4.3p2-24.el5
openssh-server-4.3p2-24.el5

and serverB has:
openssh-4.0p1-3
openssh-clients-4.0p1-3
openssh-server-4.0p1-3

Could the version differences be causing a problem? All the other machines have versions below 4.0....

mojoman,


Question,

On Server A your using what user account to perform ssh to Server B? is it root account? or just ordinary users?

If user is root account? does the system prompt you for password?

If ordinary account make sure that the /home/<username> of that user in Server B is set to 700.

Server A is root and trying to get into root of Server B......