NAME
service.switch — indicate lookup sources and fallback mechanism
DESCRIPTION
/etc/mail/service.switch
is a
sendmail(1M)
service switch similar to
/etc/nsswitch.conf
(see
switch(5))
that indicates the lookup source for hostnames and aliases.
It consists of two lines, one for hosts and one for aliases.
The lookup sources are listed after the 'hosts' or 'aliases'
name. For hosts, one or more of the following can be listed:
files (for
/etc/hosts),
dns, nis, or nisplus. For aliases,
one or more of the following can be listed: files (for
/etc/mail/aliases),
nis, or nisplus.
Sample Configurations
- 1.
The default configuration for service.switch is to use dns
for hostname lookups and the aliases file for aliases. (Note that
due to a bug, the hostname lookup will never fallback to a file
lookup, so anything listed after dns will be ignored.)
hosts dns files
aliases files
- 2.
To work with a non-dns environment that uses file lookups
(/etc/hosts),
the following service.switch can be used:
hosts files
aliases files
- 3.
To work with a NIS environment that does not use DNS, the following
service.switch can be used:
hosts nis files
aliases nis files
- 4.
To work with a NISPLUS environment that does not use DNS, the following
service.switch can be used:
hosts nisplus files
aliases nisplus files
Modifying SENDMAIL.CF
The
sendmail.cf
file must be modified to request the usage
of the
service.switch
file. Otherwise, the default for
sendmail.cf
is to use DNS for host name lookups, and files for alias lookups.
To use NIS, NISPLUS, or files, the following line must be
uncommented in
sendmail.cf:
#O ServiceSwitchFile=/etc/mail/service.switch
HISTORY
The
service.switch
file appeared in sendmail V8.