46 lines
2.4 KiB
Plaintext
46 lines
2.4 KiB
Plaintext
qmail is a secure, reliable, efficient, simple message transfer agent.
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It is meant as a replacement for the entire sendmail-binmail system on
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typical Internet-connected UNIX hosts.
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Secure: Security isn't just a goal, but an absolute requirement. Mail
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delivery is critical for users; it cannot be turned off, so it must be
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completely secure. (This is why I started writing qmail: I was sick of
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the security holes in sendmail and other MTAs.)
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Reliable: qmail's straight-paper-path philosophy guarantees that a
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message, once accepted into the system, will never be lost. qmail also
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supports maildir, a new, super-reliable user mailbox format. Maildirs,
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unlike mbox files and mh folders, won't be corrupted if the system
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crashes during delivery. Even better, not only can a user safely read
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his mail over NFS, but any number of NFS clients can deliver mail to him
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at the same time.
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Efficient: On a Pentium under BSD/OS, qmail can easily sustain 200000
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local messages per day---that's separate messages injected and delivered
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to mailboxes in a real test! Although remote deliveries are inherently
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limited by the slowness of DNS and SMTP, qmail overlaps 20 simultaneous
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deliveries by default, so it zooms quickly through mailing lists. (This
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is why I finished qmail: I had to get a big mailing list set up.)
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Simple: qmail is vastly smaller than any other Internet MTA. Some
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reasons why: (1) Other MTAs have separate forwarding, aliasing, and
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mailing list mechanisms. qmail has one simple forwarding mechanism that
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lets users handle their own mailing lists. (2) Other MTAs offer a
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spectrum of delivery modes, from fast+unsafe to slow+queued. qmail-send
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is instantly triggered by new items in the queue, so the qmail system
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has just one delivery mode: fast+queued. (3) Other MTAs include, in
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effect, a specialized version of inetd that watches the load average.
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qmail's design inherently limits the machine load, so qmail-smtpd can
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safely run from your system's inetd.
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Replacement for sendmail: qmail supports host and user masquerading,
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full host hiding, virtual domains, null clients, list-owner rewriting,
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relay control, double-bounce recording, arbitrary RFC 822 address lists,
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cross-host mailing list loop detection, per-recipient checkpointing,
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downed host backoffs, independent message retry schedules, etc. In
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short, it's up to speed on modern MTA features. qmail also includes a
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drop-in ``sendmail'' wrapper so that it will be used transparently by
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your current UAs.
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WWW: ${HOMEPAGE}
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