qmail

Spec sheet

Purpose

qmail is a secure, reliable, efficient message transfer agent for typical Internet-connected UNIX hosts.Read 9 Oct 2026 · cr.yp.to

Support

The maker directs users to the qmail mailing list and says commercial support is available through qmail.org.Read 9 Oct 2026 · cr.yp.to

License

The maker places the qmail package, specifically qmail-1.03.tar.gz, in the public domain and permits modification and redistribution.Read 9 Oct 2026 · cr.yp.to

Compatibility

qmail includes a sendmail-compatible wrapper and supports .forward and /etc/aliases through separately available tools.Read 9 Oct 2026 · cr.yp.to

Dependencies

Some listed capabilities, including parallelism limits, RBL support, and mailing-list subscription management, use separately available tools or packages.Read 9 Oct 2026 · cr.yp.to

Designed for

The maker describes qmail as designed for typical Internet-connected UNIX hosts.Read 9 Oct 2026 · cr.yp.to

Distribution terms

The maker places the qmail package in the public domain and says it may be modified and redistributed.Read 9 Oct 2026 · cr.yp.to

Download

The maker lists qmail-1.03.tar.gz as the latest published qmail package.Read 9 Oct 2026 · cr.yp.to

Mail delivery

The maker says qmail queues messages and writes local deliveries to disk before reporting success.Read 9 Oct 2026 · cr.yp.to

Mail handling

The maker lists virtual domains, relay control, host and user masquerading, and independent message retry schedules among qmail's capabilities.Read 9 Oct 2026 · cr.yp.to

Mailbox format

qmail optionally supports maildir, which the maker describes as resistant to corruption if a system crashes during delivery.Read 9 Oct 2026 · cr.yp.to

Mailboxes

qmail optionally supports Maildir, which the maker describes as resistant to corruption during delivery if the system crashes.Read 9 Oct 2026 · cr.yp.to

Mailing lists

qmail supports user-managed mailing lists, VERPs for bounce handling, and automatic loop prevention, including across hosts.Read 9 Oct 2026 · cr.yp.to

Protocols

The package includes a POP3 service with UIDL and TOP support, and its 1.03 changes added QMQP client and server support.Read 9 Oct 2026 · cr.yp.to

Related software

The maker recommends djbdns for use with qmail and lists ezmlm, ucspi-tcp, serialmail, and other related packages.Read 9 Oct 2026 · cr.yp.to

Reliability

The maker says qmail is designed so a message accepted into the system will not be lost.Read 9 Oct 2026 · cr.yp.to

Security design

The maker lists separation between addresses, files, and programs; reduced setuid and root code; and five-way trust partitioning as security features.Read 9 Oct 2026 · cr.yp.to

Sendmail compatibility

qmail includes a sendmail wrapper intended to let it be used transparently by existing user agents.Read 9 Oct 2026 · cr.yp.to

SMTP

qmail-smtpd supports relay controls, 8-bit messages, and SMTP extensions listed on the maker’s feature page.Read 9 Oct 2026 · cr.yp.to

Supported systems

The maker lists AIX, BSD/OS, FreeBSD, HP/UX, Irix, Linux, OSF/1, SunOS, and Solaris, among other UNIX variants.Read 9 Oct 2026 · cr.yp.to

Windows limit

The FAQ says qmail does not support Windows NT.Read 9 Oct 2026 · cr.yp.to

Plans and prices

Every qmail plan and price →

Where Specifiction places it

• Mail Server Software#21 of 347.8