Secure Shell Daemon Enhanced Configuration

issue.txt

This computer system is for authorized users only. Individuals using this
system without authority or in excess of their authority are subject to
having all their activities on this system monitored and recorded or
examined by any authorized person, including law enforcement, as system
personnel deem appropriate. In the course of monitoring individuals
improperly using the system or in the course of system maintenance, the
activities of authorized users may also be monitored and recorded. Any
material so recorded may be disclosed as appropriate. Anyone using this
system consents to these terms.

sshd_config.txt

# This is the sshd server system-wide configuration file.  See
# sshd_config(5) for more information.

# This sshd was compiled with PATH=/usr/local/bin:/bin:/usr/bin

# The strategy used for options in the default sshd_config shipped with
# OpenSSH is to specify options with their default value where
# possible, but leave them commented.  Uncommented options change a
# default value.

Port xxxx
Protocol 2
#ListenAddress 0.0.0.0
#ListenAddress ::

DenyUsers test admin guest nobody

# HostKey for protocol version 1
#HostKey /etc/ssh/ssh_host_key
# HostKeys for protocol version 2
#HostKey /etc/ssh/ssh_host_rsa_key
#HostKey /etc/ssh/ssh_host_dsa_key

# Lifetime and size of ephemeral version 1 server key
#KeyRegenerationInterval 1h
#ServerKeyBits 768

# Logging
#obsoletes QuietMode and FascistLogging
#SyslogFacility AUTH
SyslogFacility AUTHPRIV
LogLevel INFO

# Authentication:

LoginGraceTime 1m
PermitRootLogin yes
MaxAuthTries 4

#RSAAuthentication yes
#PubkeyAuthentication yes
AuthorizedKeysFile	.ssh/authorized_keys

# For this to work you will also need host keys in /etc/ssh/ssh_known_hosts
#RhostsRSAAuthentication no
# similar for protocol version 2
#HostbasedAuthentication no
# Change to yes if you don't trust ~/.ssh/known_hosts for
# RhostsRSAAuthentication and HostbasedAuthentication
#IgnoreUserKnownHosts 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 no to disable s/key passwords
#ChallengeResponseAuthentication yes
ChallengeResponseAuthentication	yes

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

# GSSAPI options
#GSSAPIAuthentication no
#GSSAPIAuthentication no
#GSSAPICleanupCredentials yes
#GSSAPICleanupCredentials yes

# 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 mechanism. 
# Depending on your PAM configuration, this 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 
# ChallengeResponseAuthentication=no
#UsePAM no
UsePAM	yes

#AllowTcpForwarding yes
#GatewayPorts no
#X11Forwarding no
#X11DisplayOffset 10
#X11UseLocalhost yes
PrintMotd yes
PrintLastLog yes
#TCPKeepAlive yes
#UseLogin no
UsePrivilegeSeparation yes
#PermitUserEnvironment no
Compression yes
ClientAliveInterval 120
ClientAliveCountMax 3
UseDNS no
PidFile /var/run/sshd.pid
#MaxStartups 10
ShowPatchLevel no

# no default banner path
Banner /etc/issue.net

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

# root specific authentication
Match User root
PasswordAuthentication no

You should use an SSH Key generator and create a root login shell key. It should be unique for every systems administrator. You could also create a sudo list and deny root login, entirely.

Line 102 is important for PCI compliance.

line 11 Port assignment should be set to an alternate port other than 22 and a TCP in/out rule setup in your firewall.

The contents of issue.net as your legal notification using the banner system for linux.

Line 110 Deny root login with password forces root to use a shell key.