How does Postfix format DSNs?

Postfix DSN format follows RFC standards with specific characteristics:

Structure:

MIME multipart/report format. Three parts: human-readable, machine-readable, original message.

Human-readable part:

Plain text explanation. Server name and timestamp. Error description.

Machine-readable part (message/delivery-status):

Per-recipient fields. Status codes. Diagnostic code. Remote MTA information.

Original message part:

Headers of failed message. Sometimes full message body.

Typical Postfix bounce header:

From: MAILER-DAEMON@domain.com. Subject: Undelivered Mail Returned to Sender. Includes queue ID and timestamps.

Parsing tips:

Look for "Status:" field for code. "Diagnostic-Code:" for details. "Final-Recipient:" for address.

Postfix follows RFC 3464 closely. Standard parsing works well with Postfix DSNs.