Technical data

Configuring and Managing SMTP
17.6 Configuring SMTP AntiSPAM
By default, if the SMTP server fails to find a MX record for the sender
address, it rejects the MAIL FROM command and disconnects the link.
You can specify that messages with unresolvable domains be accepted by
setting the Accept-Unresolvable-Domains configuration option to TRUE in
SMTP.CONFIG, as follows:
Accept-Unresolvable-Domains: TRUE
When Accept-Unresolvable-Domains is set, the SMTP server will not perform
an MX lookup on the sender address.
17.6.8 Specifying Handling of SPAM Events
Whenever the TCP/IP Services SMTP server disconnects a link with a client, it
generates an event message. You can control the way events are handled using
the procedures in the following sections.
17.6.8.1 Reporting SPAM Events
You can customize the SMTP server to report a SPAM event in the following
ways. The SMTP server can:
• Send an OPCOM message.
• Send a /TYPE=USER message to the accounting subsystem.
To configure the way SMTP reports the event, use the SPAM-Action field in
SMTP.CONFIG. The legal values are:
• NONE
• OPCOM (the default)
• ACCOUNTING
You can specify multiple values for the SPAM-Action field. For example:
SPAM-Action: OPCOM, ACCOUNTING
This example causes both OPCOM and accounting messages to be sent for each
SPAM event. To disable SPAM event reporting, enter a value of NONE for
SPAM-Action in SMTP.CONFIG, as follows:
SPAM-Action: NONE
17.6.8.2 Configuring SPAM Security
When the SMTP server disconnects the link with the client because of one of the
antiSPAM checks, it sends a message back to the client. The text of the message
is controlled by the Security field in SMTP.CONFIG. The legal values for this
field are:
• SECURE (the default)
If Security is set to SECURE, the messages do not indicate the cause of the
disconnect.
• FRIENDLY
If Security is set to FRIENDLY, the messages indicate the cause of the
disconnect.
Configuring and Managing SMTP 17–25