How do you transfer an SSH signature to a new server?

rchurch

I want to upgrade my OS by installing the new OS from scratch and transferring the data, ie /home directories, configuration files in /etc and so on. But if the SSH signature changes it will wreak havoc on a lot of remote connections.

How do you transfer the SSH signature to the new installation.

zhuanyi

Can you just scp the entire .ssh folder? Or make a backup of it and upload it back after the upgrade is done?

gregf

In /etc/ssh you will have some files. The ones you want to save are these.

• ssh_host_dsa_key
• ssh_host_dsa_key.pub
• ssh_host_rsa_key
• ssh_host_rsa_key.pub

Just make sure to backup these four files and copy them to /etc/ssh on the new server, replacing the existing ones there. Then restart ssh.

rchurch

If the contents of the /etc/ssh will suffice then it will be easy enough. I thought it would be more complicated than that

Mun

scp -r -P 22 [email protected]:~/.ssh/* ~/.ssh/

Please note, this isn't a really good idea, it might be a far better idea to create a new one.

rchurch

@Mun It is the server's SSH signature that is most important.

tommy

@gregf said: In /etc/ssh you will have some files. The ones you want to save are these.

ssh_host_dsa_key
ssh_host_dsa_key.pub
ssh_host_rsa_key
ssh_host_rsa_key.pub

Just make sure to backup these four files and copy them to /etc/ssh on the new server, replacing the existing ones there. Then restart ssh.

please only transfer the .pub not the private one, keep it for your self

gregf

@tommy These are the host keys not your personal keys. The server needs both.

tommy

@gregf said: These are the host keys not your personal keys. The server needs both.

I know, but why put same public and private key on all server's ? that will works but not so secure