ePrism User Guide - EdgeWave

How Messages are Processed by ePrism
How Messages are Processed by ePrism
The following sections describe the sequence in which the various ePrism security features are
applied to any inbound mail messages and how these settings affect their delivery.
SMTP Connection
An SMTP connection request is made from another system. ePrism accepts the connection
request unless one of the following checks (if enabled) is triggered:
• Reject on unauthorized SMTP pipelining — Rejects mail when the client sends SMTP
commands ahead of time without knowing that the mail server actually supports SMTP
command pipelining. This stops messages from bulk mail software that use SMTP command
pipelining improperly to speed up deliveries.
• Reject on unknown sender domain — Rejects mail when the sender mail address has no
DNS A or MX record.
• Reject on missing reverse DNS — Rejects mail from hosts where the host IP address has no
PTR (address to name) record in the DNS, or when the PTR record does not have a matching
A (name to address) record. This setting is rarely used because many servers on the Internet do
not have valid reverse DNS records, and enabling it may result in rejecting mail from legitimate
sources.
• Reject on non-FQDN sender — Rejects mail when the address in the client MAIL FROM
command is not in fully-qualified domain form (FQDN).
• Reject on Unknown Recipient — Rejects mail if the specified recipient does not exist. The
system will perform an LDAP lookup on the recipient's address to ensure they exist before
delivering the message.
• Specific Access Pattern (Reject) — The server address or other envelope field matches a
Specific Access Pattern that is set to reject the message.
Mail Header and Message Properties
The connection is now accepted. The message will be accepted for processing unless one of the
following occurs:
• Reject on missing addresses — Rejects mail when no recipients in the To: field, or no
senders in the From: field were specified in the message headers.
• Maximum number of recipients — Rejects mail if the number of recipients exceeds the
specified maximum (default = 1000).
• Maximum message size — Rejects mail if the message size exceeds the maximum.
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