The source for the sendmail program comes with a
document by the sendmail
program's authors that is required reading.
Sendmail Installation and Operations Guide
(located in doc/op in the source distribution)
provides installation instructions and a succinct description of the
configuration file. Many vendors also provide online manuals which
might reveal vendor-specific customizations not documented in this
book. Also, if you have the source, see the
RELEASE_NOTES file and all the
*/README files.
