CentOS 7でリモートVPNログインIPアドレスを制限する

バラよりman sshd_config：

 AllowUsers
         This keyword can be followed by a list of user name patterns, separated by
         spaces.  If specified, login is allowed only for user names that match one of
         the patterns.  Only user names are valid; a numerical user ID is not recog‐
         nized.  By default, login is allowed for all users.  If the pattern takes the
         form USER@HOST then USER and HOST are separately checked, restricting logins
         to particular users from particular hosts.  The allow/deny directives are
         processed in the following order: DenyUsers, AllowUsers, DenyGroups, and
         finally AllowGroups.

         See PATTERNS in ssh_config(5) for more information on patterns.

そしてman ssh_config：

PATTERNS
     A pattern consists of zero or more non-whitespace characters, ‘*’ (a wildcard that
     matches zero or more characters), or ‘?’ (a wildcard that matches exactly one charac‐
     ter).  For example, to specify a set of declarations for any host in the “.co.uk” set
     of domains, the following pattern could be used:

           Host *.co.uk

     The following pattern would match any host in the 192.168.0.[0-9] network range:

           Host 192.168.0.?

     A pattern-list is a comma-separated list of patterns.  Patterns within pattern-lists
     may be negated by preceding them with an exclamation mark (‘!’).  For example, to
     allow a key to be used from anywhere within an organisation except from the “dialup”
     pool, the following entry (in authorized_keys) could be used:

           from="!*.dialup.example.com,*.example.com"