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| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 12:06:34 +0000 |
|---|---|---|
| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 12:06:34 +0000 |
| commit | 5e61585d76ae77fd5e9e96ebabb57afa4d74880d (patch) | |
| tree | 2b467823aaeebc7ef8bc9e3cabe8074eaef1666d /html/LOCAL_RECIPIENT_README.html | |
| parent | Initial commit. (diff) | |
| download | postfix-upstream.tar.xz postfix-upstream.zip | |
Adding upstream version 3.5.24.upstream/3.5.24upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
| -rw-r--r-- | html/LOCAL_RECIPIENT_README.html | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/html/LOCAL_RECIPIENT_README.html b/html/LOCAL_RECIPIENT_README.html new file mode 100644 index 0000000..3f2e042 --- /dev/null +++ b/html/LOCAL_RECIPIENT_README.html @@ -0,0 +1,180 @@ +<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN" + "http://www.w3.org/TR/html4/loose.dtd"> + +<html> + +<head> + +<title>Rejecting Unknown Local Recipients with Postfix</title> + +<meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> + +</head> + +<body> + +<h1><img src="postfix-logo.jpg" width="203" height="98" ALT="">Rejecting Unknown Local Recipients with Postfix</h1> + +<hr> + +<h2>Introduction</h2> + +<p> As of Postfix version 2.0, the Postfix SMTP server rejects mail +for unknown recipients in <a href="ADDRESS_CLASS_README.html#local_domain_class">local domains</a> (domains that match +$<a href="postconf.5.html#mydestination">mydestination</a> or the IP addresses in $<a href="postconf.5.html#inet_interfaces">inet_interfaces</a> or +$<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a>) with "User unknown in local recipient table". +This feature was optional with earlier Postfix versions. </p> + +<p> The good news is that this keeps undeliverable mail out of your +queue, so that your mail queue is not clogged up with undeliverable +MAILER-DAEMON messages. </p> + +<p> The bad news is that it may cause mail to be rejected when you +upgrade from a Postfix system that was not configured to reject +mail for unknown local recipients. </p> + +<p> This document describes what steps are needed in order to reject +unknown local recipients correctly. </p> + +<ul> + +<li><a href="#main_config">Configuring local_recipient_maps +in main.cf</a> + +<li><a href="#change">When you need to change the local_recipient_maps +setting in main.cf</a> + +<li><a href="#format">Local recipient table format </a> + +</ul> + +<h2><a name="main_config">Configuring local_recipient_maps +in main.cf</a></h2> + +<p> The <a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> parameter specifies lookup tables with +all names or addresses of local recipients. A recipient address is +local when its domain matches $<a href="postconf.5.html#mydestination">mydestination</a>, $<a href="postconf.5.html#inet_interfaces">inet_interfaces</a> or +$<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a>. If a local username or address is not listed in +$<a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a>, then the Postfix SMTP server will reject +the address with "User unknown in local recipient table". </p> + +<p> The default setting, shown below, assumes that you use the +default Postfix <a href="local.8.html">local(8)</a> delivery agent for local delivery, where +recipients are either UNIX accounts or local aliases: </p> + +<blockquote> +<pre> +/etc/postfix/<a href="postconf.5.html">main.cf</a>: + <a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> = <a href="proxymap.8.html">proxy</a>:unix:passwd.byname $<a href="postconf.5.html#alias_maps">alias_maps</a> +</pre> +</blockquote> + +<p> To turn off unknown local recipient rejects by the SMTP server, +specify: </p> + +<blockquote> +<pre> +/etc/postfix/<a href="postconf.5.html">main.cf</a>: + <a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> = +</pre> +</blockquote> + +<p> That is, an empty value. With this setting, the Postfix SMTP +server will not reject mail with "User unknown in local recipient +table". <b> Don't do this on systems that receive mail directly +from the Internet. With today's worms and viruses, Postfix will +become a backscatter source: it accepts mail for non-existent +recipients and then tries to return that mail as "undeliverable" +to the often forged sender address</b>. </p> + +<h2><a name="change">When you need to change the local_recipient_maps +setting in main.cf</a></h2> + +<ul> + + <li> <p> Problem: you don't use the default Postfix <a href="local.8.html">local(8)</a> + delivery agent for domains matching $<a href="postconf.5.html#mydestination">mydestination</a>, $<a href="postconf.5.html#inet_interfaces">inet_interfaces</a>, + or $<a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a>. For example, you redefined the + "<a href="postconf.5.html#local_transport">local_transport</a>" setting in <a href="postconf.5.html">main.cf</a>. </p> + + <p> Solution: your <a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> setting needs to specify + a database that lists all the known user names or addresses + for that delivery agent. For example, if you deliver users in + $<a href="postconf.5.html#mydestination">mydestination</a> etc. domains via the <a href="virtual.8.html">virtual(8)</a> delivery agent, + specify: </p> + +<pre> +/etc/postfix/<a href="postconf.5.html">main.cf</a> + <a href="postconf.5.html#mydestination">mydestination</a> = $<a href="postconf.5.html#myhostname">myhostname</a> localhost.$<a href="postconf.5.html#mydomain">mydomain</a> localhost ... + <a href="postconf.5.html#local_transport">local_transport</a> = virtual + <a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> = $<a href="postconf.5.html#virtual_mailbox_maps">virtual_mailbox_maps</a> +</pre> + + <p> If you use a different delivery agent for $<a href="postconf.5.html#mydestination">mydestination</a> + etc. domains, see the section "<a href="#format">Local recipient + table format</a>" below for a description of how the table + should be populated. </p> + + <li> <p> Problem: you use the <a href="postconf.5.html#mailbox_transport">mailbox_transport</a> or <a href="postconf.5.html#fallback_transport">fallback_transport</a> + feature of the Postfix <a href="local.8.html">local(8)</a> delivery agent in order to + deliver mail to non-UNIX accounts. </p> + + <p> Solution: you need to add the database that lists the + non-UNIX users: </p> + +<pre> +/etc/postfix/<a href="postconf.5.html">main.cf</a> + <a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> = <a href="proxymap.8.html">proxy</a>:unix:passwd.byname, $<a href="postconf.5.html#alias_maps">alias_maps</a>, + <the database with non-UNIX accounts> +</pre> + + <p> See the section "<a href="#format">Local recipient table + format</a>" below for a description of how the table should be + populated. </p> + + <li> <p> Problem: you use the <a href="postconf.5.html#luser_relay">luser_relay</a> feature of the Postfix + local delivery agent. </p> + + <p> Solution: you must disable the <a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> feature + completely, so that Postfix accepts mail for all local addresses: + </p> + +<pre> +/etc/postfix/<a href="postconf.5.html">main.cf</a> + <a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> = +</pre> + +</ul> + +<h2><a name="format">Local recipient table format</a> </h2> + +<p> If you use local files in <a href="postmap.1.html">postmap(1)</a> format, then +<a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> expects the following table format: </p> + +<ul> + +<li> <p> In the left-hand side, specify a bare username, an +"@domain.tld" wild-card, or specify a complete "user@domain.tld" +address. </p> + +<li> <p> You have to specify something on the right-hand side of +the table, but the value is ignored by <a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a>. + +</ul> + +<p> If you use lookup tables based on NIS, LDAP, MYSQL, or PGSQL, +then <a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> does the same queries as for local files +in <a href="postmap.1.html">postmap(1)</a> format, and expects the same results. </p> + +<p> With regular expression tables, Postfix only queries with the +full recipient address, and not with the bare username or the +"@domain.tld" wild-card. </p> + +<p> NOTE: a lookup table should always return a result when the address +exists, and should always return "not found" when the address does +not exist. In particular, a zero-length result does not count as +a "not found" result. </p> + +</body> + +</html> |