Chapter 1: Structure of Email Services Up Main page Chapter 3: Quick Start 

2 How InterWorx Implements Email

2.1 Mail Transfer Agent

InterWorx uses Daniel J. Bernstein’s[A][A]DJB’s website can be found at qmail[B][B]Qmail’s hompage is located at as its MTA. qmail is intended to combat the largest weaknesses of the default sendmail MTA included with most Linux distributions, namely low security, speed, and reliability. qmail’s MTA consists of two primary segments: qmail-smtp, which manages the actual transfer of mail to and from the server, and qmail-send, which manages the queue. Also worth mentioning are the support components, qmail-queue (which manages the queue itself), qmail-inject (which is responsible for actually inserting messages into the queue directly), and the processes that are called by qmail-send to do the actual transferring, qmail-rspawn/qmail-lspawn and qmail-remote/qmail-local.

2.2 Mail Delivery Agents

qmail also forms one of the MDAs used by InterWorx, namely its POP3 delivery capabilities under the service name “qmail-pop3d”. IMAP4 delivery is provided by the Courier IMAP server[C][C]Courier IMAP’s website can be found at, an IMAP4 MDA known for its ability to deliver a large quantity of mail simultaneously.

2.3 Unsolicited Bulk Message Removal

For junk mail elimination, InterWorx employs SpamAssassin[D][D]SpamAssassin’s website can be found at, an automatic junk mail filter using both known spam signatures with optional user-driven bayesian filtering.

2.4 Anti-Viral Agent

SourceFire’s ClamAV[E][E]ClamAV’s website can be found at is the anti-virus of choice for InterWorx, because of its fast updates and relative simplicity.
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