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diff --git a/html/ADDRESS_CLASS_README.html b/html/ADDRESS_CLASS_README.html new file mode 100644 index 0000000..0932e9f --- /dev/null +++ b/html/ADDRESS_CLASS_README.html @@ -0,0 +1,279 @@ +<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN" + "http://www.w3.org/TR/html4/loose.dtd"> + +<html> + +<head> + +<title>Postfix Address Classes </title> + +<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> + +</head> + +<body> + +<h1><img src="postfix-logo.jpg" width="203" height="98" ALT="">Postfix Address Classes </h1> + +<hr> + +<h2>Introduction</h2> + +<p> Postfix version 2.0 introduces the concept of address classes. +This is a way of grouping recipient addresses by their delivery +method. The idea comes from discussions with Victor Duchovni. +Although address classes introduced a few incompatibilities they +also made it possible to improve the handling of <a href="VIRTUAL_README.html#canonical">hosted domains</a> +and of unknown recipients. </p> + +<p> This document provides information on the following topics: </p> + +<ul> + +<li><a href="#wtf">What are address classes good for?</a> + +<li><a href="#classes">What address classes does Postfix implement?</a> + +<li><a href="#improvements">Improvements compared to Postfix 1.1</a> + +<li><a href="#incompatibility">Incompatibilities with Postfix 1.1</a> + +</ul> + +<h2><a name="wtf">What are address classes good for?</a></h2> + +<p> Why should you care about address classes? This is how Postfix +decides what mail to accept, and how to deliver it. In other words, +address classes are very important for the operation of Postfix. </p> + +<p> An address class is defined by three items. </p> + +<ul> + +<li> <p> The list of domains that are a member of the class: for +example, all <a href="ADDRESS_CLASS_README.html#local_domain_class">local domains</a>, or all <a href="ADDRESS_CLASS_README.html#relay_domain_class">relay domains</a>. </p> + +<li> <p> The default delivery transport. For example, the local, +virtual or relay delivery transport (delivery transports are defined +in <a href="master.5.html">master.cf</a>). This helps to keep Postfix configurations simple, +by avoiding the need for explicit routing information in transport +maps. </p> + +<li> <p> The list of valid recipient addresses for that address +class. The Postfix SMTP server rejects invalid recipients with +"User unknown in <name of address class here> table". This +helps to keep the Postfix queue free of undeliverable MAILER-DAEMON +messages. </p> + +</ul> + +<h2><a name="classes">What address classes does Postfix implement?</a></h2> + +<p> Initially the list of address classes is hard coded, but this +is meant to become extensible. The summary below describes the main +purpose of each class, and what the relevant configuration parameters +are. </p> + +<p> The <a name="local_domain_class">local </a> domain class. </p> + +<ul> + +<li> <p> Purpose: final delivery for traditional UNIX system accounts +and traditional Sendmail-style aliases. This is typically used for +the <a href="VIRTUAL_README.html#canonical">canonical domains</a> of the machine. For a discussion of the +difference between <a href="VIRTUAL_README.html#canonical">canonical domains</a>, <a href="VIRTUAL_README.html#canonical">hosted domains</a> and other +domains, see the <a href="VIRTUAL_README.html">VIRTUAL_README</a> file. </p> + +<li> <p> Domain names are listed with the <a href="postconf.5.html#mydestination">mydestination</a> parameter. +This domain class also includes mail for <i>user@[ipaddress]</i> +when the IP address is listed with the <a href="postconf.5.html#inet_interfaces">inet_interfaces</a> or +<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a> parameters. </p> + +<li> <p> Valid recipient addresses are listed with the <a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> +parameter, as described in <a href="LOCAL_RECIPIENT_README.html">LOCAL_RECIPIENT_README</a>. The Postfix SMTP +server rejects invalid recipients with "User unknown in local +recipient table". If the <a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> parameter value is +empty, then the Postfix SMTP server accepts any address in the +<a href="ADDRESS_CLASS_README.html#local_domain_class">local domain</a> class. </p> + +<li> <p> The mail delivery transport is specified with the +<a href="postconf.5.html#local_transport">local_transport</a> parameter. The default value is <b><a href="local.8.html">local</a>:$<a href="postconf.5.html#myhostname">myhostname</a></b> +for delivery with the <a href="local.8.html">local(8)</a> delivery agent. </p> + +</ul> + +<p> The <a name="virtual_alias_class">virtual alias </a> domain +class. </p> + +<ul> + +<li> <p> Purpose: <a href="VIRTUAL_README.html#canonical">hosted domains</a> where each recipient address is +aliased to a local UNIX system account or to a remote address. A +<a href="VIRTUAL_README.html#virtual_alias">virtual alias example</a> is given in the <a href="VIRTUAL_README.html">VIRTUAL_README</a> file. </p> + +<li> <p> Domain names are listed in <a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a>. The +default value is $<a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a> for Postfix 1.1 compatibility. +</p> + +<li> <p> Valid recipient addresses are listed with the <a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a> +parameter. The Postfix SMTP server rejects invalid recipients with +"User unknown in virtual alias table". The default value is +$<a href="postconf.5.html#virtual_maps">virtual_maps</a> for Postfix 1.1 compatibility. </p> + +<li> <p> There is no mail delivery transport parameter. Every +address must be aliased to some other address. </p> + +</ul> + +<p> The <a name="virtual_mailbox_class">virtual mailbox </a> domain +class. </p> + +<ul> + +<li> <p> Purpose: final delivery for <a href="VIRTUAL_README.html#canonical">hosted domains</a> where each +recipient address can have its own mailbox, and where users do not +need to have a UNIX system account. A <a href="VIRTUAL_README.html#virtual_mailbox">virtual mailbox example</a> is +given in the <a href="VIRTUAL_README.html">VIRTUAL_README</a> file. </p> + +<li> <p> Domain names are listed with the <a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a> +parameter. The default value is $<a href="postconf.5.html#virtual_mailbox_maps">virtual_mailbox_maps</a> for Postfix +1.1 compatibility. </p> + +<li> <p> Valid recipient addresses are listed with the <a href="postconf.5.html#virtual_mailbox_maps">virtual_mailbox_maps</a> +parameter. The Postfix SMTP server rejects invalid recipients with +"User unknown in virtual mailbox table". If this parameter value +is empty, the Postfix SMTP server accepts all recipients for domains +listed in $<a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a>. </p> + +<li> <p> The mail delivery transport is specified with the +<a href="postconf.5.html#virtual_transport">virtual_transport</a> parameter. The default value is <b>virtual</b> +for delivery with the <a href="virtual.8.html">virtual(8)</a> delivery agent. </p> + +</ul> + +<p> The <a name="relay_domain_class">relay </a> domain class. </p> + +<ul> + +<li> <p> Purpose: mail forwarding to remote destinations that list +your system as primary or backup MX host. For a discussion of the +basic configuration details, see the <a href="BASIC_CONFIGURATION_README.html">BASIC_CONFIGURATION_README</a> +document. For a discussion of the difference between canonical +domains, <a href="VIRTUAL_README.html#canonical">hosted domains</a> and other domains, see the <a href="VIRTUAL_README.html">VIRTUAL_README</a> +file. </p> + +<li> <p> Domain names are listed with the <a href="postconf.5.html#relay_domains">relay_domains</a> parameter. +</p> + +<li> <p> Valid recipient addresses are listed with the <a href="postconf.5.html#relay_recipient_maps">relay_recipient_maps</a> +parameter. The Postfix SMTP server rejects invalid recipients with +"User unknown in relay recipient table". If this parameter value +is empty, the Postfix SMTP server accepts all recipients for domains +listed with the <a href="postconf.5.html#relay_domains">relay_domains</a> parameter. </p> + +<li> <p> The mail delivery transport is specified with the +<a href="postconf.5.html#relay_transport">relay_transport</a> parameter. The default value is <b>relay</b> which +is a clone of the <a href="smtp.8.html">smtp(8)</a> delivery agent. </p> + +</ul> + +<p> The <a name="default_domain_class">default </a> domain class. +</p> + +<ul> + +<li> <p> Purpose: mail forwarding to the Internet on behalf of +authorized clients. For a discussion of the basic configuration +details, see the <a href="BASIC_CONFIGURATION_README.html">BASIC_CONFIGURATION_README</a> file. For a discussion +of the difference between <a href="VIRTUAL_README.html#canonical">canonical domains</a>, <a href="VIRTUAL_README.html#canonical">hosted domains</a> and +other domains, see the <a href="VIRTUAL_README.html">VIRTUAL_README</a> file. </p> + +<li> <p> This class has no destination domain table. </p> + +<li> <p> This class has no valid recipient address table. </p> + +<li> <p> The mail delivery transport is specified with the +<a href="postconf.5.html#default_transport">default_transport</a> parameter. The default value is <b>smtp</b> for +delivery with the <a href="smtp.8.html">smtp(8)</a> delivery agent. </p> + +</ul> + +<h2><a name="improvements">Improvements compared to Postfix +1.1</a></h2> + +<p> Postfix 2.0 address classes made the following improvements +possible over earlier Postfix versions: </p> + +<ul> + +<li> <p> You no longer need to specify all the <a href="virtual.8.html">virtual(8)</a> mailbox +domains in the Postfix transport map. The <a href="virtual.8.html">virtual(8)</a> delivery agent +has become a first-class citizen just like <a href="local.8.html">local(8)</a> or <a href="smtp.8.html">smtp(8)</a>. +</p> + +<li> <p> On mail gateway systems, address classes provide separation +of inbound mail relay traffic ($<a href="postconf.5.html#relay_transport">relay_transport</a>) from outbound +traffic ($<a href="postconf.5.html#default_transport">default_transport</a>). This eliminates a problem where +inbound mail deliveries could become resource starved in the presence +of a high volume of outbound mail. </p> + +<li> <p> The SMTP server rejects unknown recipients in a more +consistent manner than was possible with Postfix version 1. This +is needed to keep undeliverable mail (and bounced undeliverable +mail) out of the mail queue. This is controlled by the +<a href="postconf.5.html#smtpd_reject_unlisted_recipient">smtpd_reject_unlisted_recipient</a> configuration parameter. </p> + +<li> <p> As of Postfix version 2.1, the SMTP server also rejects +unknown sender addresses (i.e. addresses that it would reject as +unknown recipient addresses). Sender "egress filtering" can help +to slow down an email worm explosion. This is controlled by the +<a href="postconf.5.html#smtpd_reject_unlisted_sender">smtpd_reject_unlisted_sender</a> configuration parameter. </p> + +</ul> + +<h2><a name="incompatibility">Incompatibilities with Postfix 1.1</a></h2> + +<p> Postfix 2.0 address classes introduce a few incompatible changes +in documented behavior. In order to ease the transitions, new +parameters have default values that are backwards compatible. </p> + +<ul> + +<li> <p> The <a href="postconf.5.html#virtual_maps">virtual_maps</a> parameter is replaced by <a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a> +(for address lookups) and by <a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a> (for the names +of what were formerly called "Postfix-style virtual domains"). </p> + +<p> For backwards compatibility with Postfix version 1.1, the new +<a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a> parameter defaults to $<a href="postconf.5.html#virtual_maps">virtual_maps</a>, and the +new <a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a> parameter defaults to $<a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a>. +</p> + +<li> <p> The <a href="postconf.5.html#virtual_mailbox_maps">virtual_mailbox_maps</a> parameter now has a companion +parameter called <a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a> (for the names of domains +served by the virtual delivery agent). The <a href="postconf.5.html#virtual_mailbox_maps">virtual_mailbox_maps</a> +parameter is now used for address lookups only. </p> + +<p> For backwards compatibility with Postfix version 1.1, the new +<a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a> parameter defaults to $<a href="postconf.5.html#virtual_mailbox_maps">virtual_mailbox_maps</a>. +</p> + +<li> <p> Introduction of the <a href="postconf.5.html#relay_recipient_maps">relay_recipient_maps</a> parameter. The +Postfix SMTP server can use this to block mail for relay recipients +that don't exist. This list is empty by default, which means accept +any recipient. </p> + +<li> <p> The <a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> feature is now turned on by +default. The Postfix SMTP server uses this to reject mail for +unknown local recipients. See the <a href="LOCAL_RECIPIENT_README.html">LOCAL_RECIPIENT_README</a> file hints +and tips. </p> + +<li> <p> Introduction of the relay delivery transport in <a href="master.5.html">master.cf</a>. +This helps to avoid mail delivery scheduling problems on inbound +mail relays when there is a lot of outbound mail, but may require +that you update your "<a href="postconf.5.html#defer_transports">defer_transports</a>" setting. </p> + +</ul> + +</body> + +</html> |