.B qmail-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
+.BR http://pobox.com/~djb/docs/smtplf.html .
.B qmail-smtpd
accepts messages that contain long lines or non-ASCII characters,
meaning every address at
.IR host .
.TP 5
+.I databytes
+Maximum number of bytes allowed in a message,
+or 0 for no limit.
+Default: 0.
+If a message exceeds this limit,
+.B qmail-smtpd
+returns a permanent error code to the client;
+in contrast, if
+the disk is full or
+.B qmail-smtpd
+hits a resource limit,
+.B qmail-smtpd
+returns a temporary error code.
+
+.I databytes
+counts bytes as stored on disk, not as transmitted through the network.
+It does not count the
+.B qmail-smtpd
+Received line, the
+.B qmail-queue
+Received line, or the envelope.
+
+If the environment variable
+.B DATABYTES
+is set, it overrides
+.IR databytes .
+.TP 5
.I localiphost
Replacement host name for local IP addresses.
Default:
This is done before
.IR rcpthosts .
.TP 5
+.I morercpthosts
+Extra allowed RCPT domains.
+If
+.I rcpthosts
+and
+.I morercpthosts
+both exist,
+.I morercpthosts
+is effectively appended to
+.IR rcpthosts .
+
+You must run
+.B qmail-newmrh
+whenever
+.I morercpthosts
+changes.
+
+Rule of thumb for large sites:
+Put your 50 most commonly used domains into
+.IR rcpthosts ,
+and the rest into
+.IR morercpthosts .
+.TP 5
.I rcpthosts
Allowed RCPT domains.
If
.B qmail-smtpd
will reject
any envelope recipient address with a domain not listed in
-.IR rcpthosts .
-
-Exception:
-If the environment variable
-.B RELAYCLIENT
-is set,
-.B qmail-smtpd
-will ignore
-.IR rcpthosts ,
-and will append the value of
-.B RELAYCLIENT
-to each incoming recipient address.
+.I rcpthosts
+unless the sending host is a designated relay client (see the
+description of the
+.I relayhosts
+file beow).
.I rcpthosts
may include wildcards:
Envelope recipient addresses without @ signs are
always allowed through.
.TP 5
+.I relayhosts
+Allowed relay clients. Each line is a host-suffix pair, separated by a
+colon. If the client's hostname matches one of the hostnames in the
+file, that client is permitted to send mail to any host (i.e., to use us
+as a relay), and the corresponding suffix is appended to all recipient
+addresses generated by the client.
+
+.I relayhosts
+may include wildcards:
+
+.EX
+ heaven.af.mil:
+ .heaven.af.mil:
+ hell.irs.gov:.irs.virtdomain
+.EE
+
+For historical reasons, the
+.B RELAYCLIENT
+environment variable overrides this table. If
+.B RELAYCLIENT
+is set, it has the same effect as there being a matching entry in the
+.I relayhosts
+file, using the value of
+.B RELAYCLIENT
+as the suffix.
+.TP 5
.I smtpgreeting
SMTP greeting message.
Default:
tcp-environ(5),
qmail-control(5),
qmail-inject(8),
+qmail-newmrh(8),
qmail-queue(8),
qmail-remote(8)