Ldap domain timeout MTA (and base) option

LDAP lookup cache MTA options:  (integer)
The  option (available at both base and MTA levels) controls the retention time (in seconds) for entries in the domain map cache. The default is -900; as the value used is the absolute value of the   setting, this corresponds to 15 minutes. If setting  explicitly, set it to a positive value so that the MTA can detect that it has indeed been intentionally set.

See also:
 * LDAP lookup cache MTA options
 * Base options