mini-smtpd - receive mail via SMTP

mini-smtpd

mini-smtpd receives mail messages via the Simple Mail Transfer Protocol (SMTP) and invokes qmail-queue to deposit them into the outgoing queue. mini-smtpd must be supplied several environment variables; see tcp-environ(5).

mini-smtpd is responsible for counting hops. It rejects any message with 100 or more Received or Delivered-To header fields.

mini-smtpd supports ESMTP, including the 8BITMIME and PIPELINING options.

mini-smtpd writes Received: header with details of the SMTP connection regarding ESMTP, date and time. If the environment variable HIDE_HOST is set, mini-smtpd does not write hostnames and IP addresses in the received header.

mini-smtpd converts the SMTP newline convention into the UNIX newline convention by converting CR LF into LF. It returns a temporary error and drops the connection on bare LFs; see https://cr.yp.to/docs/smtplf.html. If you set ALLOW_BARELF, it will accept connections on bare LFs.

mini-smtpd accepts messages that contain long lines or non-ASCII characters, even though such messages violate the SMTP protocol.

databytes
Maximum number of bytes allowed in a message, or 0 for no limit. Default: 0. If a message exceeds this limit, mini-smtpd returns a permanent error code to the client; in contrast, if the disk is full or mini-smtpd hits a resource limit, mini-smtpd returns a temporary error code.

databytes
counts bytes as stored on disk, not as transmitted through the network. It does not count the mini-smtpd Received line, the qmail-queue Received line, or the envelope.

If the environment variable DATABYTES is set, it overrides databytes.

localiphost
Replacement host name for local IP addresses. Default: me, if that is supplied. mini-smtpd is responsible for recognizing dotted-decimal addresses for the current host. When it sees a recipient address of the form box@[d.d.d.d], where d.d.d.d is a local IP address, it replaces [d.d.d.d] with localiphost. This is done before rcpthosts.

morercpthosts
Extra allowed RCPT domains. If rcpthosts and morercpthosts both exist, morercpthosts is effectively appended to rcpthosts.

You must run qmail-cdb(8) on morercpthosts whenever it changes.

Rule of thumb for large sites: Put your 50 most commonly used domains into rcpthosts, and the rest into morercpthosts.

rcpthosts
Allowed RCPT domains. If rcpthosts is supplied, mini-smtpd will reject any envelope recipient address with a domain not listed in rcpthosts.

Exception: If the environment variable RELAYCLIENT is set, mini-smtpd will ignore rcpthosts, and will append the value of RELAYCLIENT to each incoming recipient address.

rcpthosts may include wildcards:

   heaven.af.mil
   .heaven.af.mil

Envelope recipient addresses without @ signs are always allowed through.

smtpgreeting
SMTP greeting message. Default: me, if that is supplied; otherwise mini-smtpd will refuse to run. The first word of smtpgreeting should be the current host's name.

timeoutsmtpd
Number of seconds mini-smtpd will wait for each new buffer of data from the remote SMTP client. Default: 1200.

tcp-env(1), tcp-environ(5), indimail-control(5), qmail-inject(8), qmail-cdb(8), qmail-queue(8), qmta-send(8), qmail-local(8), qmail-remote(8)