Hardened config for OpenSSH config files. Be sure to update ListenAddress with IP of server.

config

#Defaults for all my hosts
Host *
        AddressFamily inet
        Ciphers [email protected],[email protected]
        ForwardX11 no
        ForwardX11Trusted no
        KexAlgorithms [email protected]
        #hmac-sha2-512 is at end of list for github support
        MACs [email protected],[email protected],[email protected],hmac-sha2-512
        Protocol 2
        VisualHostKey yes
        HashKnownHosts yes

# Example host config
Host <hostname>
        HostName <ip address>
        Port <port>
        User <user>
        IdentityFile ~/.ssh/id_ed25519_host
        PreferredAuthentications publickey

ssh_config

#  3. system-wide file
# Any configuration value is only changed the first time it is set.
# Thus, host-specific definitions should be at the beginning of the
# configuration file, and defaults at the end.

# Site-wide defaults for some commonly used options.  For a comprehensive
# list of available options, their meanings and defaults, please see the
# ssh_config(5) man page.

Host *
#   ForwardAgent no
#   ForwardX11 no
#   ForwardX11Trusted yes
#   RhostsRSAAuthentication no
#   RSAAuthentication yes
#   PasswordAuthentication yes
#   HostbasedAuthentication no
#   GSSAPIAuthentication no
#   GSSAPIDelegateCredentials no
#   GSSAPIKeyExchange no
#   GSSAPITrustDNS no
#   BatchMode no
#   CheckHostIP yes
#   AddressFamily any
#   ConnectTimeout 0
#   StrictHostKeyChecking ask
#   IdentityFile ~/.ssh/identity
#   IdentityFile ~/.ssh/id_rsa
#   IdentityFile ~/.ssh/id_dsa
#   Port 22
#   Protocol 2,1
#   Cipher 3des
#   Ciphers aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc
#   MACs hmac-md5,hmac-sha1,[email protected],hmac-ripemd160
#   EscapeChar ~
#   Tunnel no
#   TunnelDevice any:any
#   PermitLocalCommand no
#   VisualHostKey no
#   ProxyCommand ssh -q -W %h:%p gateway.example.com
#   RekeyLimit 1G 1h
##   SendEnv LANG LC_*
##   HashKnownHosts yes
##   GSSAPIAuthentication yes
##   GSSAPIDelegateCredentials no
     AddressFamily inet
     Ciphers [email protected],[email protected]
     ForwardX11 no
     ForwardX11Trusted no
     KexAlgorithms [email protected]
     MACs [email protected],[email protected],[email protected]
     Protocol 2
     VisualHostKey yes  
     HashKnownHosts yes

sshd_config

# Package generated configuration file
# See the sshd_config(5) manpage for details

# What ports, IPs and protocols we listen for
Port 22
# Use these options to restrict which interfaces/protocols sshd will bind to
#ListenAddress ::
ListenAddress 192.168.1.2
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
HostKey /etc/ssh/ssh_host_ed25519_key
#Privilege Separation is turned on for security
UsePrivilegeSeparation sandbox

# Lifetime and size of ephemeral version 1 server key
KeyRegenerationInterval 3600
ServerKeyBits 1024

# Logging
SyslogFacility AUTH
LogLevel INFO

# Authentication:
LoginGraceTime 60
PermitRootLogin no
StrictModes yes
AllowUsers matt
#DenyGroups adm #not sure I need this since I'd like to use sudo over ssh

RSAAuthentication no
PubkeyAuthentication yes
#AuthorizedKeysFile     %h/.ssh/authorized_keys
AuthorizedKeysFile /var/openssh/%u/authorized_keys

# Don't read the user's ~/.rhosts and ~/.shosts files
IgnoreRhosts yes
# For this to work you will also need host keys in /etc/ssh_known_hosts
RhostsRSAAuthentication no
# similar for protocol version 2
HostbasedAuthentication no
# Uncomment if you don't trust ~/.ssh/known_hosts for RhostsRSAAuthentication
IgnoreUserKnownHosts yes

# To enable empty passwords, change to yes (NOT RECOMMENDED)
PermitEmptyPasswords no

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

# Change to no to disable tunnelled clear text passwords
PasswordAuthentication no

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

# GSSAPI options
#GSSAPIAuthentication no
#GSSAPICleanupCredentials yes

X11Forwarding no
X11DisplayOffset 10
PrintMotd no
PrintLastLog yes
TCPKeepAlive no
ClientAliveInterval 60
ClientAliveCountMax 3
UseLogin no

MaxStartups 10:30:60
Banner /etc/issue.net

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

#Subsystem sftp /usr/lib/openssh/sftp-server

# 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 no

# Specifies the ciphers allowed for protocol version 2.
Ciphers [email protected],[email protected]

# Specifies the available KEX (Key Exchange) algorithms.
KexAlgorithms [email protected]

# Specifies the available MAC (message authentication code)
# algorithms. The algorithms that contain ``-etm'' calculate the
# MAC after encryption (encrypt-then-mac).
# These are considered safer and their use recommended.
MACs [email protected],[email protected],[email protected]