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

NOTE: You can turn off MSA in the sendmail.cf file using the option,
no_default_msa in the gen_cf script. For more information, see the
no_default_msa option in “Modifying the Default Sendmail Configuration File”
(page 43).
The XUSR SMTPcommand and the -U (initial user submission) command-line option
are deprecated. Mail user agents must use the MSA (Message Submission Agent) for
initial user message submission. XUSR may be removed in future releases. The next
release of Sendmail will assume that any message submitted from the command line
is an initial user submission and act accordingly.
Sendmail Validation
The check_compat ruleset compares all sender and receiver pairs before mail is
delivered. It validates the mail based on the results of the comparison. It checks to see
if host A can legally send a message to host B. check_compat is called for all mail
deliveries, not just SMTP transactions.
check_compat is used in the following situations:
• A set of users who are restricted from sending mail messages to external domains
need to send mail messages to internal domains. Both the sender and recipient
addresses are checked to ensure that they are in the local domain.
• A particular user needs to ensure that he or she does not receive mail messages
from a specific source.
• A particular host needs to ensure that external senders do not use that host as a a
mail relay. The mail messages are screened based on the sender’s host name.
Turning Off Virtual Interfaces
You can disable the ability to include all the interface names in the $=w macro on
startup. Turning off virtual interfaces speeds up the startup process. However, if you
turn virtual interfaces off, mail sent to those addresses will bounce back to the sender.
To turn off virtual interfaces, do the following:
1. Open the sendmail.cf file.
2. Uncomment the line DontProbeInterfaces.
By default, virtual interfaces are included in the $=w macro, which is defined in the
sendmail.cf file. Sendmail searches for them during startup.
The host name is added to class w for the names of all interfaces unless the
DontProbeInterfaces option is set. This is useful for sending mail to hosts, which
have dynamically assigned names.
Turning Off Virtual Interfaces 91