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 addrcheck.cdb
  41 A database of acceptable mailboxes.  If present, this is used to report
  42 erroneous RCPT TO commands, which can reduce the amount of junk mail
  43 accepted.  It contains an encoding of the virtual domains map
  44 .RB ( \c
  45 .BI V domain
  46 maps to
  47 .IR prefix ),
  48 the local domains
  49 .RB ( \c
  50 .BI @ domain
  51 maps to an empty string), and the available local parts
  52 .RB ( \c
  53 .BI L mailbox
  54 maps to
  55 .B +
  56 if the address is valid or
  57 .B \-
  58 if not).  It's best made using
  59 .BR qmail-valid-addresses (8).
  60 .TP 5
  61 .I addrcheck-delay
  62 Delay in seconds before reporting bad mailbox names after the
  63 .I addrcheck-slow
  64 limit is reached.  The default is 2.
  65 .TP 5
  66 .I addrcheck-limit
  67 Number of bad mailbox names to tolerate before dropping the connection.
  68 Zero means an infinite number.  The default is 50.
  69 .TP 5
  70 .I addrcheck-slow
  71 Number of bad mailbox names to tolerate before imposing delays.  The
  72 default is 5.
  73 .TP 5
  74 .I badmailfrom
  75 Unacceptable envelope sender addresses.
  76 .B qmail-smtpd
  77 will reject every recipient address for a message
  78 if the envelope sender address is listed in
  79 .IR badmailfrom .
  80 A line in
  81 .I badmailfrom
  82 may be of the form
  83 .BR @\fIhost ,
  84 meaning every address at
  85 .IR host .
  86 .TP 5
  87 .I databytes
  88 Maximum number of bytes allowed in a message,
  89 or 0 for no limit.
  90 Default: 0.
  91 If a message exceeds this limit,
  92 .B qmail-smtpd
  93 returns a permanent error code to the client;
  94 in contrast, if
  95 the disk is full or
  96 .B qmail-smtpd
  97 hits a resource limit,
  98 .B qmail-smtpd
  99 returns a temporary error code.
 100
 101 .I databytes
 102 counts bytes as stored on disk, not as transmitted through the network.
 103 It does not count the
 104 .B qmail-smtpd
 105 Received line, the
 106 .B qmail-queue
 107 Received line, or the envelope.
 108
 109 If the environment variable
 110 .B DATABYTES
 111 is set, it overrides
 112 .IR databytes .
 113 .TP 5
 114 .I localiphost
 115 Replacement host name for local IP addresses.
 116 Default:
 117 .IR me ,
 118 if that is supplied.
 119 .B qmail-smtpd
 120 is responsible for recognizing dotted-decimal addresses for the
 121 current host.
 122 When it sees a recipient address of the form
 123 .IR box@[d.d.d.d] ,
 124 where
 125 .I d.d.d.d
 126 is a local IP address,
 127 it replaces
 128 .IR [d.d.d.d]
 129 with
 130 .IR localiphost .
 131 This is done before
 132 .IR rcpthosts .
 133 .TP 5
 134 .I morercpthosts
 135 Extra allowed RCPT domains.
 136 If
 137 .I rcpthosts
 138 and
 139 .I morercpthosts
 140 both exist,
 141 .I morercpthosts
 142 is effectively appended to
 143 .IR rcpthosts .
 144
 145 You must run
 146 .B qmail-newmrh
 147 whenever
 148 .I morercpthosts
 149 changes.
 150
 151 Rule of thumb for large sites:
 152 Put your 50 most commonly used domains into
 153 .IR rcpthosts ,
 154 and the rest into
 155 .IR morercpthosts .
 156 .TP 5
 157 .I rcpthosts
 158 Allowed RCPT domains.
 159 If
 160 .I rcpthosts
 161 is supplied,
 162 .B qmail-smtpd
 163 will reject
 164 any envelope recipient address with a domain not listed in
 165 .I rcpthosts
 166 unless the sending host is a designated relay client (see the
 167 description of the
 168 .I relayhosts
 169 file beow).
 170
 171 .I rcpthosts
 172 may include wildcards:
 173
 174 .EX
 175    heaven.af.mil
 176    .heaven.af.mil
 177 .EE
 178
 179 Envelope recipient addresses without @ signs are
 180 always allowed through.
 181 .TP 5
 182 .I relayhosts
 183 Allowed relay clients.  Each line is a host-suffix pair, separated by a
 184 colon.  If the client's hostname matches one of the hostnames in the
 185 file, that client is permitted to send mail to any host (i.e., to use us
 186 as a relay), and the corresponding suffix is appended to all recipient
 187 addresses generated by the client.
 188
 189 .I relayhosts
 190 may include wildcards:
 191
 192 .EX
 193    heaven.af.mil:
 194    .heaven.af.mil:
 195    hell.irs.gov:.irs.virtdomain
 196 .EE
 197
 198 For historical reasons, the
 199 .B RELAYCLIENT
 200 environment variable overrides this table.  If
 201 .B RELAYCLIENT
 202 is set, it has the same effect as there being a matching entry in the
 203 .I relayhosts
 204 file, using the value of
 205 .B RELAYCLIENT
 206 as the suffix.
 207 .TP 5
 208 .I smtpgreeting
 209 SMTP greeting message.
 210 Default:
 211 .IR me ,
 212 if that is supplied;
 213 otherwise
 214 .B qmail-smtpd
 215 will refuse to run.
 216 The first word of
 217 .I smtpgreeting
 218 should be the current host's name.
 219 .TP 5
 220 .I timeoutsmtpd
 221 Number of seconds
 222 .B qmail-smtpd
 223 will wait for each new buffer of data from the remote SMTP client.
 224 Default: 1200.
 225 .SH "SEE ALSO"
 226 tcp-env(1),
 227 tcp-environ(5),
 228 qmail-control(5),
 229 qmail-inject(8),
 230 qmail-newmrh(8),
 231 qmail-queue(8),
 232 qmail-remote(8)