Secure Shell (SSH) 500 SSH user/group access controls. Directives are processed in the following order: deny-users, allow-users, deny-groups and allow-groups. Allow user/group SSH access Allow members of a group to login [a-z_][a-z0-9_-]{1,31}[$]? illegal characters or more than 32 characters Allow specific users to login [a-z_][a-z0-9_-]{1,31}[$]? illegal characters or more than 32 characters Deny user/group SSH access Disallow members of a group to login [a-z_][a-z0-9_-]{1,31}[$]? illegal characters or more than 32 characters Disallow specific users to login [a-z_][a-z0-9_-]{1,31}[$]? illegal characters or more than 32 characters Allowed ciphers Disable IP Address to Hostname lookup Disable password-based authentication Allowed key exchange (KEX) algorithms Local addresses SSH service should listen on ipv4 IP address to listen for incoming connections ipv6 IPv6 address to listen for incoming connections Log level QUIET stay silent FATAL log fatals only ERROR log errors and fatals only INFO default log level VERBOSE enable logging of failed login attempts Allowed message authentication code (MAC) algorithms Port for SSH service 1-65535 Numeric IP port how often send keep alives in seconds #include