sendmail, 4th Edition

Choose Preferred Agents

Four mc configuration macros are available, beginning with V8.10 sendmail, to help you choose the delivery agent you prefer in various situations.

confSMTP_MAILER

The confSMTP_MAILER mc configuration macro is used to specify your preference for the delivery agent to handle outbound SMTP connections. If you don’t define confSMTP_MAILER, the default is esmtp (The esmtp delivery agent on page 732). Other legal choices are relay (The relay delivery agent on page 733), smtp (smtp, etc. on page 731), smtp8 (The smtp8 delivery agent on page 732), and dsmtp (The dsmtp delivery agent on page 733):

define(`confSMTP_MAILER', `dsmtp')

Note that if you make a typo in the name, the error will not be detected until you actually try to send email. For example, if you misspelled dsmtp as xsmtp, you would see the following message printed and logged when trying to send a message to another machine:

buildaddr: unknown mailer xsmtp

In general, all defined mc configuration macros should precede the associated MAILER definition, but for confSMTP_MAILER, this is only a recommendation, not a requirement.

confUUCP_MAILER

The confUUCP_MAILER mc configuration macro is used to specify your preference for the delivery agent you prefer for handling UUCP. The default is uucp. Other possible values are uucp-old, uucp-new, uucp-dom, and uucp-uudom (see UUCP Support on page 606 for a discussion of these choices):

define(`confUUCP_MAILER', `uucp-dom')

If you relay all UUCP mail offsite to a special ...