qmail
qmail is an Internet Mail Transfer Agent (MTA). It
was written as a more
secure replacement for the popular Sendmail program.
qmail uses the Simple Mail Transfer Protocol (SMTP) to
exchange messages with MTA's on other systems.
Features include:
- Secure
- Clear separation between addresses, files, and programs
- Minimization of setuid code
- Minimization of root code
- Five-way trust partitioning--security in depth
- Optional logging of one-way message hashes, entire
message contents, etc.
- Message construction
- RFC 822 and RFC 1123 compliant
- Full support for address groups
- Automatic conversion of old-style address lists to RFC
822 format
sendmail command for compatibility with current user agents
- Header line length limited only by memory
- Host masquerading
- User masquerading
- Automatic Mail-Followup-To creation
- SMTP service
- RFC 821, RFC 1123, RFC 1651, RFC 1652, and RFC 1854
compliant 8-bit clean
- RFC 931/1413/ident/TAP callback--can help track
spammers/forgers
- Relay control--stops unauthorized relaying by outsiders
- No interference between relay control and aliases
- Automatic recognition of local IP addresses
- Per-buffer timeouts
- Hop counting
- Parallelism limit (via ucspi-tcp)
- Refusal of connections from known abusers (via ucspi-tcp)
- Relaying and message rewriting for authorized clients
- Optional RBL/ORBS support (via rblsmtpd)
- Reliable
- Efficient - performing up to 20 deliveries simultaneously,
by default
- Queue management
- Instant handling of messages added to queue
- Parallelism limits
- Split queue directory--no slowdown when queue gets big
- Quadratic retry schedule--old messages tried less often
- Independent message retry schedules
- Automatic safe queueing--no loss of mail if system crashes
- Automatic per-recipient checkpointing
- Automatic queue cleanups
- Queue viewing
- Detailed delivery statistics (via qmailanalog)
- Bounces
- QSBMF bounce messages--both machine-readable and
human-readable
- HCMSSC support--language-independent RFC 1893 error codes
- Double bounces sent to postmaster
- Routing by domain
- Any number of names for local host
- Any number of virtual domains
- Domain wildcards
- Configurable "percent hack" support
- UUCP hook
- SMTP delivery
- RFC 821, RFC 974, and RFC 1123 compliant
- 8-bit clean
- Automatic downed host backoffs
- Artificial routing--smarthost, localnet, mailertable
- per-buffer timeouts
- Passive SMTP queue--perfect for SLIP/PPP
- AutoTURN support (via serialmail)
- Forwarding and mailing lists
- Sendmail .forward compatibility (via dot-forward)
- Hashed forwarding databases (via fastforward)
- Sendmail /etc/aliases compatibility (via fastforward)
- Address wildcards
- Mailing list owners--automatically divert bounces and
vacation messages
- VERPs--automatic recipient identification for mailing
list bounces
- Delivered-To--automatic loop prevention, even across hosts
- Local delivery
- User-controlled address hierarchy--fred controls
fred-anything mbox delivery
- Reliable NFS delivery
- User-controlled program delivery: procmail etc
- Optional new-mail notification
- Optional NRUDT return receipts
- Conditional filtering
- POP3 service
- RFC 1939 compliant
- UIDL support
- TOP support
- APOP hook
- modular password checking (via checkpassword)
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Last Updated Sunday, November 25 2012 @ 12:40 PM EST |