Sendmail, 3rd Edition

Name

ServiceSwitchFile

Synopsis

Some implementations of Unix recognize that system information can be found in a variety of places. On Solaris 8, for example, hostnames can be obtained from the /etc/hosts file, from nis, from nisplus, or from DNS. Solaris allows the system administrator to choose the order in which these services are searched with a “service-switch” file. Other systems, such as Ultrix and DEC OSF/1, have a similar concept, but some (such as SunOS 4) use built-in rules that cannot be changed without the source code.

Beginning with V8.7, sendmail uses a system-service switch on Solaris, DEC OSF/1, and Ultrix.^[62] Otherwise, sendmail uses the service switch defined by this ServiceSwitchFile option.

The form for redefining the switched-services file is as follows:

O ServiceSwitchFile=path             ← configuration file (V8.7 and later) 
-OServiceSwitchFile=path             ← command line (V8.7 and later) 
define(`confSERVICE_SWITCH_FILE',path)← mc configuration (V8.7 and later) 

If this option is defined on Solaris, DEC OSF/1, or Ultrix, it is ignored. Otherwise, path is used as the full pathname of the file that is to be used as the service switch. If path is omitted, the default is NULL. If the entire option is omitted, the default is /etc/mail/service.switch. The default for the mc technique is to omit this option.

The service-switch file must live in a safe directory and must itself have safe permissions, or sendmail will refuse to use the information in it. If your site unavoidably must ...