Few days ago I migrated my website to a new server, and whenever you try to connect to a server using ssh it must known it first, if not it will complain, and ask you verfiy the server key signature: $ ssh rayed.com The authenticity of host 'rayed.com (x.x.x.x)' can't be established. : Are you sure you want to continue connecting (yes/no/[fingerprint])? If you say yes, it will add the server signature to your system as known host, in the file ~/.

Finally I managed to migrate from Centos 7 to Debian. The migration was motivated by two updates: Debian has improved a lot, specially in the field of ease of use, I can now recommend it without hesitation. Redhat decided to stop supporting Centos as a downstream version from its own OS, it is now continuous update OS similar to Fedora but for the server version. Thank you Redhat but I don’t think I can rely on it any more.

Update System # switch to user root su - apt update && apt upgrade apt install sudo usermod -aG sudo rayed # logout from root & user Network Enable New Interface Ref: https://wiki.debian.org/NetworkConfiguration sudo vi /etc/network/interfaces : auto enp0s8 iface enp0s8 inet dhcp : sudo ifup enp0s8 NTP sudo vi /etc/systemd/timesyncd.conf : NTP=sa.pool.ntp.org : sudo systemctl restart systemd-timesyncd timedatectl timesync-status Security Secure SSH sudo vi /etc/ssh/sshd_config : PasswordAuthentication no : sudo systemctl restart ssh Firewall Ref: https://wiki.