Sendmail 8.11.1 Release Notes

• Spam Control using Message Submission Agent (RFC 2476)
Message Submission Protocol is a means for MUAs to introduce new messages
into the message transfer agent routing network. Messages being submitted by
MUAs, in some cases, may be unfinished. Unfinished messages need to be
completed by the MSA before submitting to the MTA. It also helps in implementing
authenticated submission, including off-site submission by authorized users such
as travellers.
The messages received on port 587 are regarded as "submitted messages". MSAs
may implement message rejection rules, i.e. if an MSA is unable to determine a
return path for the submitting user, from a valid MAIL FROM, a valid source IP
address, or based on authenticated identity, then the MSA will immediately reject
the message, as it gives the user and MUA direct feedback.
Sendmail 8.11.1 supports RFC 2476, a protocol for message submission. The
anti-spam rulesets have been enhanced to improve the anti-spam capabilities. The
RFC proposes a new standard for the Message Submission Agent (MSA). This is
designed to replace the more general-purpose mail transfer agent (MTA) as the
first service to which a Mail User Agent (MUA) connects to deliver a mail message.
The RFC also describes how the usual protocols for SMTP service should be
tightened up at the point where mail enters the system, rather than being routed
from one site to another.Sendmail 8.11.1 also serves as a powerful tool to
authenticate and control mail messages.
By default, MSA is defined in the sendmail.cf file as:
O DaemonPortOptions=Name=MSA, Port=587, M=E
where Port 587 is reserved for email message submission.
A Message Submission Agent still uses all of the same rulesets for processing the
message (and therefore still allows message rejection via the check_* rulesets). In
accordance with the RFC, the MSA will ensure that all domains in the envelope
are fully qualified if the message is relayed to another MTA. It will also enforce
the normal address syntax rules and log error messages. In addition to the above,
you can request authentication before the messages are accepted by MSA by using
theM=a modifier in the DaemonPortOptions.
10 New and Changed Features