23.5 Database Maps with mc Configuration

All available mc database maps are implemented as mc features. Table 23-4 lists those that are available. The second column shows you where to find information about each.

Table 23-4. Database-map features
Feature	§	Version	Description
`access_db`	Section 7.5	V8.9 and above	A database for mail policy
`authinfo`	FEATURE(authinfo)	V8.12 and above	Use a separate database for authentication information
`bestmx_is_local`	FEATURE(bestmx_is_local)	V8.6 and above	Accept best MX record as local if in `$=w`
`bitdomain`	FEATURE(bitdomain)	Deprecated	Convert BITNET addresses into Internet addresses
`dnsbl`	Section 7.2	V8.10 and above	Reject based on various DNS blacklists
`domaintable`	FEATURE(domaintable)	V8.1 and above	Accept other domains as equivalent to the local domain
`enhdnsbl`	Section 7.2.2	V8.12 and above	Enhanced `dnsbl` lookups
`genericstable`	FEATURE(genericstable)	V8.8 and above	Transform sender addresses
`ldap_routing`	See this section	V8.10 and above	Reroute recipients based on LDAP lookups
`mailertable`	FEATURE(mailertable)	V8.1 and above	Select new delivery agents based on an external database
`uucpdomain`	FEATURE(uucpdomain)	Deprecated	Convert UUCP hosts via a database
`virtusertable`	FEATURE(virtusertable)	V8.8 and above	Support for virtual domains

Note that these features do not necessarily need to be used with database files. To illustrate, consider the domaintable feature (FEATURE(domaintable)). It is included in your mc file like this:

FEATURE(`domaintable',`nis domaintable')

Here, we specify that the database map is to be the nis type. This causes the key to be looked up via NIS and any match to be returned the same way.

23.5.1 Set a Default Database-Map Type for Features

Features that employ on-disk database files all share the common default database-map type hash. But if you wish to change that default to another type, you can do so with the following mc configuration command:

define(`DATABASE_MAP_TYPE', `dbm')

Here, we declare the default to be dbm, thereby causing all such features to use ndbm(3) database files. Note that if you declare a default, you must do so before declaring any database features.

Many features that take arguments require you to declare the database type. For example:

FEATURE(`authinfo', `dbm /etc/security/authinfo')

That is, this DATABASE_MAP_TYPE's default is used only if no argument is given for the feature.

23.5 Database Maps with mc Configuration

Table 23-4. Database-map features

23.5.1 Set a Default Database-Map Type for Features