Protocol 2

# LogLevel VERBOSE

HostKey /etc/ssh/host_keys/rsa

# https://cipherli.st/
KexAlgorithms curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256
Ciphers chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr
MACs hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,umac-128@openssh.com

PermitRootLogin no
PubkeyAuthentication yes
# > RSA: The length of the modulus n shall be 2048 bits or more to meet the
# > minimum security-strength requirement of 112 bits [...]
# https://csrc.nist.gov/publications/detail/sp/800-131a/rev-2/final
RequiredRSASize 2048
PasswordAuthentication no
StrictModes no
# separated by spaces
AllowUsers _

ForceCommand /bin/false
AllowAgentForwarding no
AllowTcpForwarding all
GatewayPorts no
PermitTunnel no
X11Forwarding no
PermitUserEnvironment no
PermitTTY no
PrintMotd no