# TCP port to bind to
# Change to a high/odd port if this server is exposed to the internet directly
Port 7743

# Deny all other users besides the following
AllowUsers {{ user }}

# Bind to all interfaces (change to specific interface if needed)
ListenAddress 0.0.0.0

# Force SSHv2 Protocol
Protocol 2

# HostKeys for protocol version 2
HostKey /etc/ssh/ssh_host_rsa_key
HostKey /etc/ssh/ssh_host_dsa_key
HostKey /etc/ssh/ssh_host_ecdsa_key

HostKeyAlgorithms ssh-rsa,rsa-sha2-512,rsa-sha2-256

# Privilege Separation is turned on for security
UsePrivilegeSeparation yes

# Public key authentication + Password authentication
# Two-Factor Authentication in OpenSSH v6.2+
RSAAuthentication yes
PubkeyAuthentication yes
AuthenticationMethods publickey

# Disable root SSH access
PermitRootLogin no

# Client timeout (5 minutes)
ClientAliveInterval 300
ClientAliveCountMax 0

# Compression (only after authentication)
Compression delayed

# Logging
SyslogFacility AUTH
LogLevel INFO

# Authentication must happen within 30 seconds
LoginGraceTime 30

PermitEmptyPasswords no

# Check user folder permissions before allowing access
StrictModes yes

# Message Authentication Code (Hash, only SHA2-512)
# SHA-256 included for compat with PuTTY-WinCrypt clients
MACs hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,umac-128-etm@openssh.com

# Ciphers (only secure AES-256)
Ciphers aes256-ctr,aes128-gcm@openssh.com,aes128-ctr,aes192-ctr,aes256-gcm@openssh.com,chacha20-poly1305@openssh.com

# Key Exchange algorithms (Elliptic Curve Diffie-Hellman)
# DH-SHA-256 included for compat with PuTTY-WinCrypt clients
KexAlgorithms diffie-hellman-group18-sha512,curve25519-sha256@libssh.org

# Don’t read the user’s ~/.rhosts and ~/.shosts files
IgnoreRhosts yes

# Disable unused authentication schemes
RhostsRSAAuthentication no
HostbasedAuthentication no
ChallengeResponseAuthentication no
KerberosAuthentication no
GSSAPIAuthentication no
UsePAM no

# X11 support
X11Forwarding no

# Don’t show Message of the Day
PrintMotd yes

# TCPKeepAlive (non-tunneled, disabled)
TCPKeepAlive no

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

Subsystem sftp internal-sftp