ssh ssh-keygen authorizedkeys and knownhosts

ssh ssh-keygen

authorizedkeys

contains ssh keys of users that you want to allow to connect to this server with passwordless access

knownhosts

contains ssh keys of hosts/servers that you want to allow to connect to this server

https://www.baeldung.com/linux/public-key-known_hosts
https://linuxhandbook.com/known-hosts-file/
https://www.howtouselinux.com/post/ssh-known_hosts-file