How to create trust between servers via ssh keys

[Jayraj]

Hi All,

I am getting the following error, while trying to login to a server1.How to create trust between Server2 and Server1

Server2$ sudo ssh Server1
Warning: the RSA host key for 'Server1' differs from the key for the IP address '153.6.190.168'
Offending key for IP in /wdroot/.ssh/known_hosts:522
Matching host key in /wdroot/.ssh/known_hosts:894
Are you sure you want to continue connecting (yes/no)?

[Mel Burslan · Accepted solution]

before anything else, I'd try deleting the offending key.

edit /wdroot/.ssh/known_hosts
goto line 522
delete line
save and exit
retry and if it does not work, come back here post the new error message you are getting.

[Jayraj]

Hi,
Here is the No of lines in known_hosts in each server

Server1 #"known_hosts" 20 lines, 9248 characters
Server2 #"known_hosts" 939 lines, 496928 characters

There is no Line 522 in server1.

[Mel Burslan]

line number 522 on the server initiating the ssh connection. You said from server2 to server1 and your server2 has a pretty fat known_hosts file. Edit that one or simply do this:

cat /wdroot/.ssh/known_hosts | sed -e "522,522d" > /tmp/kh
cat /tmp/kh > /wdroot/.ssh/known_hosts

this should do it.

[Steven E. Protter]

Shalom,

http://www.hpux.ws/?p=10

Remove the offending keys as indicated. Use vi.

SEP

[Jayraj]

Hi,

I have another question..

is it possible to make trust, if the user dont have his ID on server 2.

Can we make trust between two diffrent users..?

[Steven E. Protter]

Shalom again,

You ask:

is it possible to make trust, if the user dont have his ID on server 2.

Can we make trust between two diffrent users..?

Yes.

The document I posted has a step. You take the users public key .pub transfer it to the server you wish it to log into.

Create or append a file in the .ssh directory called authorized_keys

If you have in the authorized_keys file for user shmuel the public key for user donny from another server a "trust" relationship as you call it is established. I call it exchange of public keys.

SEP

[Mel Burslan]

The answer is yes and no.

Yes you can create trust but no, it will not trust by default.

Lets say:
You are user2 on server2
You want to ssh to server1 as user1
You have a private key on server2 at /home/user2/.ssh/id_rsa
And you have complementary public key on server1 inside /home/user1/.ssh/authorized_keys file

to get to user1@server1 from user2@server2 all you need to do is

On server2
# ssh -l user1 server1

[Jayraj]

Hi,

Here is the problem, User dont have his ID on server1. So if I removed the offending key..
will he be going to login in server1 as root..?

[Berd]

Jayraj,

Please see link to prior thread which explains setting up from scratch.

http://forums13.itrc.hp.com/service/forums/questionanswer.do?threadId=1125086

Regards,
Berd

[Mel Burslan]

>User dont have his ID on server1. So if I removed the offending key..
>will he be going to login in server1 as root..?

unless you specify which username to use on the remote server with -l switch, it will use your local login name. If you are root on server2, running command:

ssh server1

will use root username on server1, whereas

ssh -l user1 server12

will try to login as user1 on the remote server.

There has to be a username to log in as on the remote server otherwise your attempt will be refused, regardless if you are using "-l username" or just letting it go default. Lack of username specification will not default your login as root, as you are expecting, if I'm not misunderstanding,

[Jayraj]

Thank you all, its done..