ZCS Administrator Guide 8.0

Network Edition

How Archiving Works

When a message is sent or received by a user, the message is always routed through the Postfix MTA. The Postfix MTA allows integrating software that can perform actions on messages that are in flight. When archiving is enabled for the sender or the recipient of messages, Zimbra Archiving integrates with an MTA hook and the Amavisd-New utility to fork a copy of the message.

The “does recipient or sender have archiving enabled” check is performed on the SMTP standard envelope and not on the From or To/Cc headers. Since checks are performed on the envelope, Bcc copies and messages sent to distribution lists are captured.

For example, if User A sends a message to User B, and if User B has archiving enabled, the MTA delivers two messages — one to User B’s mailbox and one to User B’s archive mailbox. The message received in User B’s mailbox looks normal, as shown in the following example:

 

Received: from localhost (localhost.localdomain [127.0.0.1])… From: userA@example.com To:userB@example.com Subject: New License Key Message-ID: <015f01c717fe$70f042d1$b1d6f61d@thom> Date: Mon, 04 Nov 2008 23:48:18 -0000   Hi B, Can you send me the license key for the software again? Thanks, A

The message received in User B’s archive mailbox contains additional X-Envelope-From and X-Envelope-To headers. These headers show the real email address the message was sent from and each of the email addresses that the message was sent to.

 

Received: from localhost (localhost.localdomain [127.0.0.1])… From: userA@example.com To:userB@example.com Subject: New License Key Message-ID: <015f01c717fe$70f042d1$b1d6f61d@thom> X-Envelope-From: userA@example.com X-Envelope-To: userB@example.com Date: Mon, 04 Nov 2008 23:48:18 -0000   Hi B, Can you send me the license key for the software again? Thanks, A

Zimbra archiving can be set up to create archiving accounts that are maintained within ZCS or to work with third-party archiving systems using SMTP forwarding to send messages to a third-party archive server. For third-party archiving, ZCS is configured to act as the forwarding agent.