# OpenSSH rugged config

# listen on ssh port, security is not "choice another port"
Port 22

# ipv6 only
AddressFamily inet6
ListenAddress ::

# ed25519 only
HostKey /etc/ssh/ssh_host_ed25519_key

# SSH CA
TrustedUserCAKeys /etc/ssh/ca-vault.pem

# Cipher and algorithms
KexAlgorithms curve25519-sha256@libssh.org
Ciphers chacha20-poly1305@openssh.com
MACs hmac-sha2-512-etm@openssh.com

# Logging
SyslogFacility AUTH
LogLevel INFO

# Authentication
LoginGraceTime 10s
PermitRootLogin prohibit-password
StrictModes yes
MaxAuthTries 2
MaxSessions 10

# Allow publickey
PubkeyAuthentication yes

# Expect .ssh/authorized_keys2 to be disregarded by default in future.
#AuthorizedKeysFile	.ssh/authorized_keys .ssh/authorized_keys2

#AuthorizedPrincipalsFile none

#AuthorizedKeysCommand none
#AuthorizedKeysCommandUser nobody

# For this to work you will also need host keys in /etc/ssh/ssh_known_hosts
HostbasedAuthentication no
# Don't read the user's ~/.rhosts and ~/.shosts files
IgnoreRhosts yes

# To disable tunneled clear text passwords, change to no here!
#PasswordAuthentication yes
#PermitEmptyPasswords no

# Change to yes to enable challenge-response passwords (beware issues with
# some PAM modules and threads)
ChallengeResponseAuthentication no

# Kerberos options
KerberosAuthentication no
#KerberosOrLocalPasswd yes
#KerberosTicketCleanup yes
#KerberosGetAFSToken no

# GSSAPI options
GSSAPIAuthentication no
#GSSAPICleanupCredentials yes
#GSSAPIStrictAcceptorCheck yes
#GSSAPIKeyExchange no

# Set this to 'yes' to enable PAM authentication, account processing,
# and session processing. If this is enabled, PAM authentication will
# be allowed through the ChallengeResponseAuthentication and
# PasswordAuthentication.  Depending on your PAM configuration,
# PAM authentication via ChallengeResponseAuthentication may bypass
# the setting of "PermitRootLogin without-password".
# If you just want the PAM account and session checks to run without
# PAM authentication, then enable this but set PasswordAuthentication
# and ChallengeResponseAuthentication to 'no'.
UsePAM yes

#AllowAgentForwarding yes
#AllowTcpForwarding yes
#GatewayPorts no
#X11DisplayOffset 10
#X11UseLocalhost yes
#PermitTTY yes
#PrintLastLog yes
#TCPKeepAlive yes
#PermitUserEnvironment no
#Compression delayed
#ClientAliveInterval 0
#ClientAliveCountMax 3
#PidFile /var/run/sshd.pid
#PermitTunnel no
#ChrootDirectory none

MaxStartups 10:30:100
X11Forwarding no
UseDNS no
PrintMotd no
VersionAddendum none

# no default banner path
Banner none
DebianBanner no

# Allow client to pass locale environment variables
AcceptEnv LANG LC_*

# override default of no subsystems
Subsystem	sftp	/usr/lib/openssh/sftp-server