SSH2 Client to SSH3 Server "non-password" fails

[Mark_541]

Hello,

I have a SSH2 Client (HP-UX 11) that has to connect to SSH3 server (HP-UX 11).

I have follow the procedure using ssh-keygen and copying the key from the client id_rsa_2048_b.pub (SSH2) to the server
authorized_keys..

However, still have the prompt to enter the password .. :-(

I have attached an SSH session using the debug mode (v).

BR

[Mark_541]

Here is the trace.

[Matti_Kurkela · Accepted solution]

There are currently two main variants of SSH: OpenSSH-related ones and the commercial ones. They are interoperable, but there are some differences in key storage and management.

For OpenSSH-related SSHs, the public key is formatted as a single *long* line of text.

For commercial SSHs, it is a multi-line block of text with "---- BEGIN SSH2 PUBLIC KEY ----" and "---- END SSH2 PUBLIC KEY ----" delimiters.

Your server seems to be OpenSSH-related, so the public key should be appended to .ssh/authorized_keys as you seem to have done. However, the key *MUST* be in OpenSSH format for this to work. You can convert the key with *OpenSSH-related* ssh-keygen utility with this command:
ssh-keygen -i -f id_rsa_2048_b.pub >opensshformat.pub

Remove the commercial-style key from the authorized_keys file and put the converted key in there.

In addition, with a commercial SSH client (as you seem to have), you must define which key you are going to use for authentication at the client end. This is done by creating a file named .ssh2/identification. It should contain a directive "IdKey" and the name of the private key you want to use. In your case, it would probably be:
IdKey id_rsa_2048_b

Without this, the commercial SSH client won't even try to use the key for authentication (you can see in the trace that the client is looking for /home/user1/.ssh2/identification but is unable to open it, probably because it does not exist).

[Mark_541]

Hello Matti,

I will try this but for sure you have gussed the whole things: Yes, Client is commercial SSH2 and server is OpenSSH v3.

Any other advise regarding the config file on the SSH 2 Client (ssh_config or sshd_config). Enabling RSA auth for instance etc..

Thanks in advance

[Mark_541]

Well done Matti :-)

Thx lot.