[Discuss] SSH and Server OS Migration

[Eric Chadbourne]

On 9/8/21 9:26 AM, jbk wrote:
> I am migrating my home file and backup server from SL 7 to Rocky 8 in a 
> dual boot arrangement. It serves three or four other notebooks and 
> workstation. The backup program (BackupPC) uses ssh on the client 
> machines to call rsync and transmit the backup data.
> What I though I could do so that I didn't have to update the 
> "knownhosts" file on all machines was to substitute the public and 
> private keys on Rocky with those from SL 7 ( /etc/ssh). This did not 
> work, as I get the error fingerprint does not match from other machine.
> I thought I had done this 10 years ago when I last upgraded the server. 
> Since then SSH has changed the allowed key types (dsa to escda) for 
> better encryption and I had to go through the process of updating the 
> keys and knownhost files on all the machines.
> It is going to take me a while to get the backup server configured on 
> Rocky so I will be continuing to use SL 7 during this process.
> Is it possible to substitute the keys on Rocky for those on SL 7?
> 


I think you can either write a two line bash script to remove and add 
the keys, or look at StrictHostKeyChecking.

Eric