mdw@git.distorted.org.uk Git - qmail/blob - qmail-smtpd.8

   1 .TH qmail-smtpd 8
   2 .SH NAME
   3 qmail-smtpd \- receive mail via SMTP
   4 .SH SYNOPSIS
   5 .B qmail-smtpd
   6 .SH DESCRIPTION
   7 .B qmail-smtpd
   8 receives mail messages via the Simple Mail Transfer Protocol (SMTP)
   9 and invokes
  10 .B qmail-queue
  11 to deposit them into the outgoing queue.
  12 .B qmail-smtpd
  13 must be supplied several environment variables;
  14 see
  15 .BR tcp-environ(5) .
  16
  17 .B qmail-smtpd
  18 is responsible for counting hops.
  19 It rejects any message with 100 or more
  20 .B Received
  21 or
  22 .B Delivered-To
  23 header fields.
  24
  25 .B qmail-smtpd
  26 supports ESMTP, including the 8BITMIME and PIPELINING options.
  27 .SH TRANSPARENCY
  28 .B qmail-smtpd
  29 converts the SMTP newline convention into the UNIX newline convention
  30 by converting CR LF into LF.
  31 It returns a temporary error and drops the connection on bare LFs;
  32 see
  33 .BR http://pobox.com/~djb/docs/smtplf.html .
  34
  35 .B qmail-smtpd
  36 accepts messages that contain long lines or non-ASCII characters,
  37 even though such messages violate the SMTP protocol.
  38 .SH "CONTROL FILES"
  39 .TP 5
  40 .I badmailfrom
  41 Unacceptable envelope sender addresses.
  42 .B qmail-smtpd
  43 will reject every recipient address for a message
  44 if the envelope sender address is listed in
  45 .IR badmailfrom .
  46 A line in
  47 .I badmailfrom
  48 may be of the form
  49 .BR @\fIhost ,
  50 meaning every address at
  51 .IR host .
  52 .TP 5
  53 .I databytes
  54 Maximum number of bytes allowed in a message,
  55 or 0 for no limit.
  56 Default: 0.
  57 If a message exceeds this limit,
  58 .B qmail-smtpd
  59 returns a permanent error code to the client;
  60 in contrast, if
  61 the disk is full or
  62 .B qmail-smtpd
  63 hits a resource limit,
  64 .B qmail-smtpd
  65 returns a temporary error code.
  66
  67 .I databytes
  68 counts bytes as stored on disk, not as transmitted through the network.
  69 It does not count the
  70 .B qmail-smtpd
  71 Received line, the
  72 .B qmail-queue
  73 Received line, or the envelope.
  74
  75 If the environment variable
  76 .B DATABYTES
  77 is set, it overrides
  78 .IR databytes .
  79 .TP 5
  80 .I localiphost
  81 Replacement host name for local IP addresses.
  82 Default:
  83 .IR me ,
  84 if that is supplied.
  85 .B qmail-smtpd
  86 is responsible for recognizing dotted-decimal addresses for the
  87 current host.
  88 When it sees a recipient address of the form
  89 .IR box@[d.d.d.d] ,
  90 where
  91 .I d.d.d.d
  92 is a local IP address,
  93 it replaces
  94 .IR [d.d.d.d]
  95 with
  96 .IR localiphost .
  97 This is done before
  98 .IR rcpthosts .
  99 .TP 5
 100 .I morercpthosts
 101 Extra allowed RCPT domains.
 102 If
 103 .I rcpthosts
 104 and
 105 .I morercpthosts
 106 both exist,
 107 .I morercpthosts
 108 is effectively appended to
 109 .IR rcpthosts .
 110
 111 You must run
 112 .B qmail-newmrh
 113 whenever
 114 .I morercpthosts
 115 changes.
 116
 117 Rule of thumb for large sites:
 118 Put your 50 most commonly used domains into
 119 .IR rcpthosts ,
 120 and the rest into
 121 .IR morercpthosts .
 122 .TP 5
 123 .I rcpthosts
 124 Allowed RCPT domains.
 125 If
 126 .I rcpthosts
 127 is supplied,
 128 .B qmail-smtpd
 129 will reject
 130 any envelope recipient address with a domain not listed in
 131 .I rcpthosts
 132 unless the sending host is a designated relay client (see the
 133 description of the
 134 .I relayhosts
 135 file beow).
 136
 137 .I rcpthosts
 138 may include wildcards:
 139
 140 .EX
 141    heaven.af.mil
 142    .heaven.af.mil
 143 .EE
 144
 145 Envelope recipient addresses without @ signs are
 146 always allowed through.
 147 .TP 5
 148 .I relayhosts
 149 Allowed relay clients.  Each line is a host-suffix pair, separated by a
 150 colon.  If the client's hostname matches one of the hostnames in the
 151 file, that client is permitted to send mail to any host (i.e., to use us
 152 as a relay), and the corresponding suffix is appended to all recipient
 153 addresses generated by the client.
 154
 155 .I relayhosts
 156 may include wildcards:
 157
 158 .EX
 159    heaven.af.mil:
 160    .heaven.af.mil:
 161    hell.irs.gov:.irs.virtdomain
 162 .EE
 163
 164 For historical reasons, the
 165 .B RELAYCLIENT
 166 environment variable overrides this table.  If
 167 .B RELAYCLIENT
 168 is set, it has the same effect as there being a matching entry in the
 169 .I relayhosts
 170 file, using the value of
 171 .B RELAYCLIENT
 172 as the suffix.
 173 .TP 5
 174 .I smtpgreeting
 175 SMTP greeting message.
 176 Default:
 177 .IR me ,
 178 if that is supplied;
 179 otherwise
 180 .B qmail-smtpd
 181 will refuse to run.
 182 The first word of
 183 .I smtpgreeting
 184 should be the current host's name.
 185 .TP 5
 186 .I timeoutsmtpd
 187 Number of seconds
 188 .B qmail-smtpd
 189 will wait for each new buffer of data from the remote SMTP client.
 190 Default: 1200.
 191 .SH "SEE ALSO"
 192 tcp-env(1),
 193 tcp-environ(5),
 194 qmail-control(5),
 195 qmail-inject(8),
 196 qmail-newmrh(8),
 197 qmail-queue(8),
 198 qmail-remote(8)