NAME

service.switch − indicate lookup sources and fallback mechanism

SYNOPSIS

/etc/mail/service.switch

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.) 

hostsdns files
aliasesfiles

2.  To work with a non-dns environment that uses file lookups (/etc/hosts), the following service.switch can be used:

hostsfiles
aliasesfiles

3.  To work with a NIS environment that does not use DNS, the following service.switch can be used:

hostsnis files
aliasesnis files

4.  To work with a NISPLUS environment that does not use DNS, the following service.switch can be used:

hostsnisplus files
aliasesnisplus 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

SEE ALSO

sendmail(1M)

HISTORY

The service.switch file appeared in sendmail V8. 

Hewlett-Packard Company  —  HP-UX Release 10.20:  July 1996