333 lines
12 KiB
HTML
333 lines
12 KiB
HTML
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<html> <head> </head> <body> <pre>
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SMTPD(8) SMTPD(8)
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<b>NAME</b>
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smtpd - Postfix SMTP server
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<b>SYNOPSIS</b>
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<b>smtpd</b> [generic Postfix daemon options]
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<b>DESCRIPTION</b>
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The SMTP server accepts network connection requests and
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performs zero or more SMTP transactions per connection.
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Each received message is piped through the <a href="cleanup.8.html"><b>cleanup</b>(8)</a> dae-
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mon, and is placed into the <b>incoming</b> queue as one single
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queue file. For this mode of operation, the program
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expects to be run from the <a href="master.8.html"><b>master</b>(8)</a> process manager.
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Alternatively, the SMTP server takes an established con-
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nection on standard input and deposits messages directly
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into the <b>maildrop</b> queue. In this so-called stand-alone
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mode, the SMTP server can accept mail even while the mail
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system is not running.
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The SMTP server implements a variety of policies for con-
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nection requests, and for parameters given to <b>HELO,</b> <b>MAIL</b>
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<b>FROM,</b> <b>VRFY</b> and <b>RCPT</b> <b>TO</b> commands. They are detailed below
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and in the <b>main.cf</b> configuration file.
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<b>SECURITY</b>
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The SMTP server is moderately security-sensitive. It talks
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to SMTP clients and to DNS servers on the network. The
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SMTP server can be run chrooted at fixed low privilege.
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<b>STANDARDS</b>
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<a href="http://www.faqs.org/rfcs/rfc821.html">RFC 821</a> (SMTP protocol)
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<a href="http://www.faqs.org/rfcs/rfc1123.html">RFC 1123</a> (Host requirements)
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<a href="http://www.faqs.org/rfcs/rfc1651.html">RFC 1651</a> (SMTP service extensions)
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<a href="http://www.faqs.org/rfcs/rfc1652.html">RFC 1652</a> (8bit-MIME transport)
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<a href="http://www.faqs.org/rfcs/rfc1854.html">RFC 1854</a> (SMTP Pipelining)
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<a href="http://www.faqs.org/rfcs/rfc1870.html">RFC 1870</a> (Message Size Declaration)
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<a href="http://www.faqs.org/rfcs/rfc1985.html">RFC 1985</a> (ETRN command) (partial)
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<b>DIAGNOSTICS</b>
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Problems and transactions are logged to <b>syslogd</b>(8).
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Depending on the setting of the <b>notify</b><i>_</i><b>classes</b> parameter,
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the postmaster is notified of bounces, protocol problems,
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policy violations, and of other trouble.
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<b>BUGS</b>
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<a href="http://www.faqs.org/rfcs/rfc1985.html">RFC 1985</a> is implemented by forcing delivery of all
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deferred mail.
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<b>CONFIGURATION</b> <b>PARAMETERS</b>
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The following <b>main.cf</b> parameters are especially relevant
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to this program. See the Postfix <b>main.cf</b> file for syntax
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details and for default values. Use the <b>postfix</b> <b>reload</b>
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1
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SMTPD(8) SMTPD(8)
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command after a configuration change.
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<b>Compatibility</b> <b>controls</b>
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<b>strict</b><i>_</i><b>rfc821</b><i>_</i><b>envelopes</b>
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Disallow non-<a href="http://www.faqs.org/rfcs/rfc821.html">RFC 821</a> style addresses in envelopes.
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For example, allow <a href="http://www.faqs.org/rfcs/rfc822.html">RFC822</a>-style address forms with
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comments, like Sendmail does.
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<b>Miscellaneous</b>
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<b>always</b><i>_</i><b>bcc</b>
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Address to send a copy of each message that enters
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the system.
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<b>command</b><i>_</i><b>directory</b>
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Location of Postfix support commands (default:
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<b>$program</b><i>_</i><b>directory</b>).
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<b>debug</b><i>_</i><b>peer</b><i>_</i><b>level</b>
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Increment in verbose logging level when a remote
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host matches a pattern in the <b>debug</b><i>_</i><b>peer</b><i>_</i><b>list</b>
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parameter.
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<b>debug</b><i>_</i><b>peer</b><i>_</i><b>list</b>
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List of domain or network patterns. When a remote
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host matches a pattern, increase the verbose log-
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ging level by the amount specified in the
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<b>debug</b><i>_</i><b>peer</b><i>_</i><b>level</b> parameter.
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<b>error</b><i>_</i><b>notice</b><i>_</i><b>recipient</b>
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Recipient of protocol/policy/resource/software
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error notices.
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<b>hopcount</b><i>_</i><b>limit</b>
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Limit the number of <b>Received:</b> message headers.
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<b>notify</b><i>_</i><b>classes</b>
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List of error classes. Of special interest are:
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<b>local</b><i>_</i><b>recipient</b><i>_</i><b>maps</b>
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List of maps with user names that are local to
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<b>$myorigin</b> or <b>$inet</b><i>_</i><b>interfaces</b>. If this parameter is
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defined, then the SMTP server rejects mail for
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unknown local users.
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<b>policy</b> When a client violates any policy, mail a
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transcript of the entire SMTP session to the
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postmaster.
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<b>protocol</b>
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When a client violates the SMTP protocol or
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issues an unimplemented command, mail a
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transcript of the entire SMTP session to the
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postmaster.
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2
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SMTPD(8) SMTPD(8)
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<b>smtpd</b><i>_</i><b>banner</b>
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Text that follows the <b>220</b> status code in the SMTP
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greeting banner.
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<b>smtpd</b><i>_</i><b>recipient</b><i>_</i><b>limit</b>
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Restrict the number of recipients that the SMTP
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server accepts per message delivery.
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<b>smtpd</b><i>_</i><b>timeout</b>
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Limit the time to send a server response and to
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receive a client request.
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<b>Resource</b> <b>controls</b>
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<b>line</b><i>_</i><b>length</b><i>_</i><b>limit</b>
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Limit the amount of memory in bytes used for the
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handling of partial input lines.
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<b>message</b><i>_</i><b>size</b><i>_</i><b>limit</b>
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Limit the total size in bytes of a message, includ-
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ing on-disk storage for envelope information.
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<b>queue</b><i>_</i><b>minfree</b>
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Minimal amount of free space in bytes in the queue
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file system for the SMTP server to accept any mail
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at all.
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<b>Tarpitting</b>
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<b>smtpd</b><i>_</i><b>error</b><i>_</i><b>sleep</b><i>_</i><b>time</b>
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Time to wait in seconds before sending a 4xx or 5xx
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server error response.
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<b>smtpd</b><i>_</i><b>soft</b><i>_</i><b>error</b><i>_</i><b>limit</b>
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When an SMTP client has made this number of errors,
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wait <i>error_count</i> seconds before responding to any
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client request.
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<b>smtpd</b><i>_</i><b>hard</b><i>_</i><b>error</b><i>_</i><b>limit</b>
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Disconnect after a client has made this number of
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errors.
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<b>smtpd</b><i>_</i><b>junk</b><i>_</i><b>command</b><i>_</i><b>limit</b>
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Limit the number of times a client can issue a junk
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command such as NOOP, VRFY, ETRN or RSET in one
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SMTP session before it is penalized with tarpit
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delays.
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<b>UCE</b> <b>control</b> <b>restrictions</b>
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<b>smtpd</b><i>_</i><b>client</b><i>_</i><b>restrictions</b>
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Restrict what clients may connect to this mail sys-
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tem.
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<b>smtpd</b><i>_</i><b>helo</b><i>_</i><b>required</b>
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Require that clients introduce themselves at the
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beginning of an SMTP session.
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3
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SMTPD(8) SMTPD(8)
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<b>smtpd</b><i>_</i><b>helo</b><i>_</i><b>restrictions</b>
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Restrict what client hostnames are allowed in <b>HELO</b>
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and <b>EHLO</b> commands.
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<b>smtpd</b><i>_</i><b>sender</b><i>_</i><b>restrictions</b>
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Restrict what sender addresses are allowed in <b>MAIL</b>
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<b>FROM</b> commands.
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<b>smtpd</b><i>_</i><b>recipient</b><i>_</i><b>restrictions</b>
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Restrict what recipient addresses are allowed in
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<b>RCPT</b> <b>TO</b> commands.
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<b>smtpd</b><i>_</i><b>etrn</b><i>_</i><b>restrictions</b>
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Restrict what domain names can be used in <b>ETRN</b> com-
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mands, and what clients may issue <b>ETRN</b> commands.
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<b>allow</b><i>_</i><b>untrusted</b><i>_</i><b>routing</b>
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Allow untrusted clients to specify addresses with
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sender-specified routing. Enabling this opens up
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nasty relay loopholes involving trusted backup MX
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hosts.
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<b>restriction</b><i>_</i><b>classes</b>
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Declares the name of zero or more parameters that
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contain a list of UCE restrictions. The names of
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these parameters can then be used instead of the
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restriction lists that they represent.
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<b>maps</b><i>_</i><b>rbl</b><i>_</i><b>domains</b>
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List of DNS domains that publish the addresses of
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blacklisted hosts.
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<b>relay</b><i>_</i><b>domains</b>
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Restrict what domains or networks this mail system
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will relay mail from or to.
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<b>UCE</b> <b>control</b> <b>responses</b>
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<b>access</b><i>_</i><b>map</b><i>_</i><b>reject</b><i>_</i><b>code</b>
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Server response when a client violates an access
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database restriction.
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<b>invalid</b><i>_</i><b>hostname</b><i>_</i><b>reject</b><i>_</i><b>code</b>
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Server response when a client violates the
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<b>reject</b><i>_</i><b>invalid</b><i>_</i><b>hostname</b> restriction.
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<b>maps</b><i>_</i><b>rbl</b><i>_</i><b>reject</b><i>_</i><b>code</b>
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Server response when a client violates the
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<b>maps</b><i>_</i><b>rbl</b><i>_</i><b>domains</b> restriction.
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<b>reject</b><i>_</i><b>code</b>
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Response code when the client matches a <b>reject</b>
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restriction.
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4
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SMTPD(8) SMTPD(8)
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<b>relay</b><i>_</i><b>domains</b><i>_</i><b>reject</b><i>_</i><b>code</b>
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Server response when a client attempts to violate
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the mail relay policy.
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<b>unknown</b><i>_</i><b>address</b><i>_</i><b>reject</b><i>_</i><b>code</b>
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Server response when a client violates the
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<b>reject</b><i>_</i><b>unknown</b><i>_</i><b>address</b> restriction.
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<b>unknown</b><i>_</i><b>client</b><i>_</i><b>reject</b><i>_</i><b>code</b>
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Server response when a client without address to
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name mapping violates the <b>reject</b><i>_</i><b>unknown</b><i>_</i><b>clients</b>
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restriction.
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<b>unknown</b><i>_</i><b>hostname</b><i>_</i><b>reject</b><i>_</i><b>code</b>
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Server response when a client violates the
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<b>reject</b><i>_</i><b>unknown</b><i>_</i><b>hostname</b> restriction.
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<b>SEE</b> <b>ALSO</b>
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<a href="cleanup.8.html">cleanup(8)</a> message canonicalization
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<a href="master.8.html">master(8)</a> process manager
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syslogd(8) system logging
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<b>LICENSE</b>
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The Secure Mailer license must be distributed with this
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software.
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<b>AUTHOR(S)</b>
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Wietse Venema
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IBM T.J. Watson Research
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P.O. Box 704
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Yorktown Heights, NY 10598, USA
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5
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</pre> </body> </html>
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