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Smail \- Installation and Administration Guide
.AU
Ronald S. Karr <tron@uts.amdahl.com>
Landon Curt Noll <chongo@uts.amdahl.com>
.AI
Amdahl Corp.
1250 E. Arques Ave.
Sunnyvale, CA  94088-3470
.AB ABSTRACT
.PP
.B Smail3.1
is a router and transport agent for mail.  It receives mail messages
and recipient addresses from local users and remote hosts, routes mail
destined for remote hosts, performs alias and forwarding
transformations on local addresses and performs delivery.
.B Smail
can be used in any networking environment that expects mail to conform
to the DDN mail format standards; for example, the ARPAnet, CS-Net and
the international UUCP network.
.PP
The mailer can be used to route mail between any number of
conforming networks, and can use a variety of methods for determining
the namespace on those networks and performing delivery.  The three
mutually orthogonal operations of aliasing, host routing and transport
are all handled in a consistent manner with consistent configuration
file formats and C language drivers to implement the basic
capabilities.
.PP
A number of tools are included in the smail distribution which are
useful in building, maintaining and displaying databases.  Some of
these tools operate on databases used by the mailer itself.  Others
are useful for users and site administrators.
.PP
This paper describes the
.B smail
installation procedure, the methodologies to use in constructing
configurations, tools for building databases, and administration
concerns that must be addressed.
.AE
.NH
Introduction
.PP
The
.B smail3.1
program and its associated utilities were developed to provide an
extensible mailer that conforms to the DDN mail format standards in
the ARPAnet
.I "Request For Comment"
documents RFC822, RFC920 and RFC976.  It can also accept and transmit
mail conforming to the transmission envelope format standard described
in RFC821.
.PP
A major design goal was to provide extensibility in the methods
employed for resolving local and remote addresses, and in the methods
used for performing mail delivery.  This extensibility is provided
through drivers that provide basic services on the level of C language
subroutines, and run-time configuration files which define parameters
that specify how these drivers are to used.  The run-time
configuration files are not required, and if they do not exist then
pre-loaded configurations are used.  This allows many sites to operate
with no run-time configuration files.
.PP
Another goal was to provide a reliable mail service that was tolerant
of system crashes and capable of recovering from configuration errors.
To a limited extent, smail was also designed to recover from file
systems that run out of space, and from log files that cannot be
opened or written to.
.PP
In addition to these and other goals, we felt that it was also
important that
.B smail
be compatible with the external interface of the Berkeley
.B sendmail
program.  This compatibility applies to the command line options, to
as large an extent as was feasible, but does not apply to either the
internal operation or the configuration file formats.  Indeed the
configuration files for
.B smail
and for
.B sendmail
differ not only in their format, but also in their philosophy and in
what they describe.  The
.B sendmail
configuration files describe a syntax-directed model of recipient
address routing, while the
.B smail
configuration files describe a database model of recipient address
routing, and local address matching and expansion.
