Sendmail, 3rd Edition

Name

host

Synopsis

The host database-map type is a special internal database used by sendmail to help resolve hostnames. It is fully described under the $[ and $] operators in Section 23.4.3.

Only a few database-map switches are available with the host type, and they are listed in Table 23-15.

Table 23-15. The host database-map type K command switches

Switch	§	Description
-a	-a	Append tag on successful match
-d	See this section	The res_search( ) _res.retry interval (V8.12 and above)
-D	-D	Don’t use this database map if DeliveryMode=defer
-m	-m	Suppress replacement on match
-r	See this section	The res_search( ) _res.retries limit (V8.12 and above)
-S	-S	Space replacement character
-T	-T	Suffix to append on temporary failure
-t	-t	Ignore temporary errors

The -D database switch should probably always be used with this type on sites that have dial-on-demand connections to the Internet. It prevents host lookups when the DeliveryMode option (DeliveryMode) is set to defer.