# ******************************************************************************
#
# SSH server configuration file
#
# OpenSSH_8.2p1 - Ubuntu 20.04 LTS Server
# See the sshd_config(5) manpage for details
# ******************************************************************************

# Include the specified configuration file(s)
# Included files will override any options defined furher below
Include /etc/ssh/sshd_config.d/*.conf


# -------------------------------------
# Network and Protocol
# -------------------------------------
# On which TCP ports we listen for SSH client connections
Port 63508

# On which interfaces and IP addresses we listen for SSH client connections
#ListenAddress ::
#ListenAddress 0.0.0.0


# -------------------------------------
# Server Authentication
# -------------------------------------

# HostKeys for protocol version 2 - by order of preference
HostKey /etc/ssh/ssh_host_ed25519_key
HostKey /etc/ssh/ssh_host_rsa_key

# The host key algorithms that the server will offer
HostKeyAlgorithms ssh-ed25519,ssh-ed25519-cert-v01@openssh.com,sk-ssh-ed25519@openssh.com,sk-ssh-ed25519-cert-v01@openssh.com,rsa-sha2-256,rsa-sha2-512,rsa-sha2-256-cert-v01@openssh.com,rsa-sha2-512-cert-v01@openssh.com


# -------------------------------------
# Client and User Authentication
# -------------------------------------

# Root login is not allowed for auditing reasons.
# Regular user logins combined with "sudo" ensures a clear audit track.
PermitRootLogin no
#PermitRootLogin without-password

# Only public-key based logins are allowed. Disables password based logins.
AuthenticationMethods publickey

# Don't allow challenge-response passwords
ChallengeResponseAuthentication no

# Disable tunneled clear text passwords
PasswordAuthentication no

# Enable PAM authentication
# If enabled, make sure that 'PasswordAuthentication' and
# 'ChallengeResponseAuthentication' are both set to 'no'.
UsePAM yes

# Don't print /etc/motd when a user logs in
PrintMotd no

# Only users who are member of the following groups are allowed to login
AllowGroups sshlogin


# -------------------------------------
# Ciphers Suites Selections
# -------------------------------------

# Key Exchange (KEX) Algorithms
KexAlgorithms curve25519-sha256,curve25519-sha256@libssh.org,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512

# Symmetric ciphers
Ciphers chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr

# Message authentication
MACs hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,umac-128-etm@openssh.com


# -------------------------------------
# Allowed Client Features
# -------------------------------------

# Whether X11 forwarding is permitted
X11Forwarding no

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

# Secure File Transfer Protocol
Subsystem sftp /usr/lib/openssh/sftp-server

# Remove any existing Unix-domain socket file for local or remote port
# forwarding before creating a new one. The default is no.
StreamLocalBindUnlink yes

# -*- mode: ssh_config; indent-tabs-mode: nil; tab-width: 4; -*-