Just allow strong algorithms:
echo “MACs hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512,hmac-sha2-256” >> /etc/ssh/sshd_config
echo “KexAlgorithms sntrup761x25519-sha512@openssh.com,curve25519-sha256,curve25519-sha256@libssh.org” >> /etc/ssh/sshd_config
echo “disable_vrfy_command=yes” >> /etc/postfix/main.cf
Change SSH Port
Do not use default port 22
