[Discuss] SSH and Server OS Migration

[jbk at kjkelra.com (jbk)]

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?

-- 
Jim Kelly-Rand
jbk at kjkelra.com