Sendmail Installation and Operation Guide
SMM:08-79
The built-in map with both name and class "host" is the host name canonicalization lookup.
Thus, the syntax:
$(host hostname$)
is equivalent to:
$[hostname$]
There are many defined classes.
dbm
Database lookups using the ndbm(3) library. Sendmail must be compiled with
NDBM
defined.
btree
Database lookups using the btree interface to the Berkeley DB library. Sendmail
must be compiled with NEWDB defined.
hash
Database lookups using the hash interface to the Berkeley DB library. Sendmail
must be compiled with NEWDB defined.
nis NIS lookups. Sendmail must be compiled with NIS defined.
nisplus NIS+ lookups. Sendmail must be compiled with NISPLUS defined. The argu-
ment is the name of the table to use for lookups, and the -k and -v flags may be
used to set the key and value columns respectively.
hesiod Hesiod lookups. Sendmail must be compiled with HESIOD defined.
ldap
LDAP X500 directory lookups. Sendmail must be compiled with LDAPMAP
defined. The map supports most of the standard arguments and most of the com-
mand line arguments of the ldapsearch program. Note that, by default, if a single
query matches multiple values, only the first value will be returned unless the -z
(value separator) map flag is set. Also, the -1 map flag will treat a multiple value
return as if there were no matches.
netinfo NeXT NetInfo
lookups. Sendmail must be compiled with NETINFO defined.
text
Text file lookups. The format of the text file is defined by the -k (key field num-
ber), -v (value field number), and -z (field delimiter) flags.
ph
PH query map. Contributed and supported by Mark Roth, roth@uiuc.edu. For
more information, consult the web site "http://www-dev.cites.uiuc.edu/sendmail/".
nsd
nsd map for IRIX 6.5 and later. Contributed and supported by Bob Mende of
SGI, mende@sgi.com.
stab
Internal symbol table lookups. Used internally for aliasing.
implicit
Really should be called "alias" -- this is used to get the default lookups for alias
files, and is the default if no class is specified for alias files.
user
Looks up users using getpwnam(3). The -v flag can be used to specify the name
of the field to return (although this is normally used only to check the existence of
a user).
host
Canonifies host domain names. Given a host name it calls the name server to find
the canonical name for that host.
bestmx
Returns the best MX record for a host name given as the key. The current
machine is always preferred -- that is, if the current machine is one of the hosts
listed as a lowest-preference MX record, then it will be guaranteed to be returned.
This can be used to find out if this machine is the target for an MX record, and
mail can be accepted on that basis. If the -z flag is given, then all MX names are
returned, separated by the given delimiter.