topic Re: re-generating ssh host keys in Operating System - HP-UX

re-generating ssh host keys

Michael O'brien_1 — Thu, 12 Apr 2007 11:06:39 GMT

Hi,

I've recently cloned a box using ignite. I would now like to regenerate the host keys in /etc/opt/ssh/ssh_host*

Can anybody tell me how to re-generate the host keys

Thanks
Michael

Re: re-generating ssh host keys

Sundar_7 — Thu, 12 Apr 2007 11:07:56 GMT

ssh-keygen -t dsa

Will do.

Re: re-generating ssh host keys

Michael O'brien_1 — Thu, 12 Apr 2007 11:20:23 GMT

Hi Sundar,

I need to re-generate the host keys rather than user keys. When I run the ssh-keygen -t dsa, this will promote me to create the ./ssh/id_dsa rather than /etc/opt/ssh/ssh_host_key

Thanks
Michael

Re: re-generating ssh host keys

Sameer_Nirmal — Thu, 12 Apr 2007 12:04:38 GMT

Remove the existing host/pub (rsa/dsa) keys.
Generate ssh host keys using as per your requirements.

# ssh-keygen -t (rsa/dsa) -f /etc/opt/ssh/ssh_host_{rsa/dsa}_key -N ''

Re: re-generating ssh host keys

Sameer_Nirmal — Thu, 12 Apr 2007 12:07:06 GMT

Note there is a space between the two quotation marks afer -N

This is because host key generation requires a null new passphrase.

Re: re-generating ssh host keys

Michael O'brien_1 — Thu, 12 Apr 2007 12:17:43 GMT

Hi Sameer,

Thanks for the reply, I'm okay with generating the ssh_host_rsa_key and ssh_host_dsa_key. In the /etc/opt/ssh directory it has 3 sets of keys

ssh_host_rsa_key
ssh_host_dsa_key
ssh_host_key

How do you generate the ssh_host_key

Thanks
Michael

Re: re-generating ssh host keys

Sundar_7 — Thu, 12 Apr 2007 12:17:52 GMT

Michael,

ssh-keygen can be used to create both user's and hosts' SSH keys.

You can specific the file name /etc/opt/ssh/ssh_host* in the prompt.

That will create the SSH key for the host.

Sundar.

Re: re-generating ssh host keys

Sundar_7 — Thu, 12 Apr 2007 12:21:43 GMT

Michael,

By default only /opt/ssh/etc/ssh_host_dsa_key is used.

Verify your SSH server configuration.

# grep "HostKey" /etc/opt/ssh/sshd_config

Sundar.

Re: re-generating ssh host keys

Sameer_Nirmal — Thu, 12 Apr 2007 12:39:50 GMT

Using following command, you can create the key.

# ssh-keygen -f /etc/opt/ssh/ssh_host_key -N ''

Re: re-generating ssh host keys

Steven E. Protter — Thu, 12 Apr 2007 12:48:58 GMT

Shalom Michael,

ssh-keygen -t rsa

Generates a smaller key file.

SEP

Re: re-generating ssh host keys

Heironimus — Thu, 12 Apr 2007 14:38:50 GMT

ssh_host_key is the ssh1 RSA key. You can create those with "ssh-keygen -t rsa1".