HP-UX Mailing Services Administrator's Guide (B2355-91064)

host name changes repeatedly. In this case, authorization is via a secret password,
which is client dependent.
The authentication protocol exchange consists of a series of server challenges (otherwise
known as a ready response) and client answers that are specific to the authentication
mechanism.
The AUTH parameter to the MAIL FROMcommand is set as follows:
MAIL FROM: from-addr AUTH=addr-spec
The addr-spec contains the identity that submitted the message to the delivery system.
If the server trusts the authenticated identity of the client to assert that the message
was originally submitted by the supplied addr-spec, then the server must supply
the same addr-spec in an AUTH parameter when relaying the message to any server
that supports the AUTH extension.
You can specify the list of authentication mechanisms for AUTH in the AuthMechanisms
option in the sendmail.cf file. By default, it appears in the sendmail.cf file as
follows:
#O AuthMechanisms=GSSAPI KERBEROS_V4 DIGEST-MD5 CRAM-MD5
If you set this option to A, the AUTH= parameter for theMAIL FROM command is issued
only when authentication succeeds.
DaemonPortOptions has a suboption called modifiers (M). The modifiers
suboption contains an authentication flag a, which instructs the daemon to authenticate
all its connections.
By default, it appears in the sendmail.cf file as:
#O DefaultAuthInfo=/etc/mail/default-auth-info
The DefaultAuthInfo option sets the file name, which by default contains the
authentication information for outgoing connections. It must contain the authorization
ID (userid), the authentication ID (authid), the password (plain text), and the realm
to use, each on a separate line. This information must be readable only by root (or by
the trusted user). If you do not specify a realm, $j is used.
SMTP Pipelining
This feature is an extension of the SMTP service. It enables a server to indicate the
extent to which it can accept multiple commands in a single TCP send operation. Using
a single TCP send operation for multiple commands improves the SMTP performance.
SMTP pipelining is an implementation of RFC 1854 (SMTP Service Extension for Command
Pipelining).
76 Configuring and Administering Sendmail