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.