Client access to Message Store servers

The TCP client access control mechanism used by Message Store servers such as the  POP and IMAP servers,  and proxy servers such as the  MMP and MSHTTP,  uses TCP wrappers. The ENS server also uses this mechanism.

Note that the MMP behaves a bit differently with respect to access control than do the other services, in that the MMP " " service controls both IMAP and IMAP+SSL services; that is, it controls both ports 143 and 993. In contrast, other Messaging Server services treat IMAP and IMAP+SSL as separate services, each with their own separate access control.

See also the  option, which may be used to limit the number of connections, (rather than outright blocking). And see the  options, such as , which may be configured to penalize failed authentication attempts.

For allowing inspection of (rather than controlling/limiting) when a user last accessed the Message Store, see the   base option. For allowing inspection of what users are currently connected via the IMAP server or via the  MSHTTP server, see the    IMAP and MSHTTP  options. And see the  utility for displaying such information.

For access control on the MTA&#x27;s SMTP server and other Dispatcher services, see instead Mail filtering and access control and in particular the    mapping table.

See also:
 * TCP wrappers
 * connlimits Option
 * bgpenalty Option
 * Mail filtering and access control
 * Connection access control
 * Defending against denial of service attacks
 * PORT_ACCESS mapping table
 * Dispatcher
 * ENS options
 * IMAP options
 * MMP and IMAP Proxy and POP Proxy and vdomain options
 * MSHTTP options
 * POP options
 * enablelastaccess Option
 * enableuserlist Option
 * The Message Store