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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:46:30 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:46:30 +0000 |
commit | b5896ba9f6047e7031e2bdee0622d543e11a6734 (patch) | |
tree | fd7b460593a2fee1be579bec5697e6d887ea3421 /html/COMPATIBILITY_README.html | |
parent | Initial commit. (diff) | |
download | postfix-upstream.tar.xz postfix-upstream.zip |
Adding upstream version 3.4.23.upstream/3.4.23upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'html/COMPATIBILITY_README.html')
-rw-r--r-- | html/COMPATIBILITY_README.html | 395 |
1 files changed, 395 insertions, 0 deletions
diff --git a/html/COMPATIBILITY_README.html b/html/COMPATIBILITY_README.html new file mode 100644 index 0000000..d527e19 --- /dev/null +++ b/html/COMPATIBILITY_README.html @@ -0,0 +1,395 @@ +<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN" + "http://www.w3.org/TR/html4/loose.dtd"> + +<html> + +<head> + +<title>Postfix Backwards-Compatibility Safety Net</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="">Postfix +Backwards-Compatibility Safety Net</h1> + +<hr> + +<h2>Purpose of this document </h2> + +<p> Postfix 3.0 introduces a safety net that runs Postfix programs +with backwards-compatible default settings after an upgrade. The +safety net will log a warning whenever a "new" default setting could +have an negative effect on your mail flow. </p> + +<p>This document provides information on the following topics: </p> + +<ul> + +<li> <p> <a href="#overview">Detailed descriptions</a> of Postfix +backwards-compatibility warnings. + +<li> <p> What backwards-compatible settings you may have to make +permanent in <a href="postconf.5.html">main.cf</a> or <a href="master.5.html">master.cf</a>. </p> + +<li> <p> <a href="#turnoff">How to turn off</a> Postfix +backwards-compatibility warnings. </p> + +</ul> + +<h2> <a name="overview"> Overview </a> </h2> + +<p> With backwards compatibility turned on, Postfix logs a message +whenever a backwards-compatible default setting may be required for +continuity of service. Based on this logging the system administrator +can decide if any backwards-compatible settings need to be made +permanent in main.cf or master.cf, before <a href="#turnoff">turning +off the backwards-compatibility safety net</a> as described at the +end of this document. </p> + +<p> The following messages may be logged: </p> + +<ul> + +<li> <p> <a href="#append_dot_mydomain"> Using backwards-compatible +default setting append_dot_mydomain=yes </a> </p> + +<li> <p> <a href="#chroot"> Using backwards-compatible default setting +chroot=y</a> </p> + +<li><p> <a href="#relay_restrictions"> Using backwards-compatible +default setting smtpd_relay_restrictions = (empty)</a> </p> + +<li> <p> <a href="#mynetworks_style"> Using backwards-compatible +default setting mynetworks_style=subnet </a> </p> + +<li> <p> <a href="#relay_domains"> Using backwards-compatible default +setting relay_domains=$mydestination </a> </p> + +<li> <p> <a href="#smtputf8_enable"> Using backwards-compatible +default setting smtputf8_enable=no</a> </p> + +</ul> + +<p> If such a message is logged in the context of a legitimate +request, the system administrator should make the backwards-compatible +setting permanent in <a href="postconf.5.html">main.cf</a> or <a href="master.5.html">master.cf</a>, as detailed in the +sections that follow. </p> + +<p> When no more backwards-compatible settings need to be made +permanent, the system administrator should <a href="#turnoff">turn +off the backwards-compatibility safety net</a> as described at the +end of this document. </p> + +<h2> <a name="append_dot_mydomain"> Using backwards-compatible default +setting append_dot_mydomain=yes</a> </h2> + +<p> The <a href="postconf.5.html#append_dot_mydomain">append_dot_mydomain</a> default value has changed from "yes" +to "no". This could result in unexpected non-delivery of email after +Postfix is updated from an older version. The backwards-compatibility +safety net is designed to prevent such surprises. </p> + +<p> As long as the <a href="postconf.5.html#append_dot_mydomain">append_dot_mydomain</a> parameter is left at +its implicit default value, and the <a href="postconf.5.html#compatibility_level">compatibility_level</a> setting is +less than 1, Postfix may log one of the following messages:</p> + +<ul> + +<li> <p> Messages about missing "localhost" in <a href="postconf.5.html#mydestination">mydestination</a> or +other address class: </p> + +<blockquote> +<pre> +postfix/trivial-rewrite[14777]: using backwards-compatible + default setting <a href="postconf.5.html#append_dot_mydomain">append_dot_mydomain</a>=yes to rewrite + "localhost" to "localhost.example.com"; please add + "localhost" to <a href="postconf.5.html#mydestination">mydestination</a> or other address class +</pre> +</blockquote> + +<p> If Postfix logs the above message, add "localhost" to +<a href="postconf.5.html#mydestination">mydestination</a> (or <a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a>, <a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a>, +or <a href="postconf.5.html#relay_domains">relay_domains</a>) and execute the command "<b>postfix reload</b>". + +<li> <p> Messages about incomplete domains in email addresses: </p> + +<blockquote> +<pre> +postfix/trivial-rewrite[25835]: using backwards-compatible + default setting <a href="postconf.5.html#append_dot_mydomain">append_dot_mydomain</a>=yes to rewrite "foo" to + "foo.example.com" +</pre> +</blockquote> + +<p> If Postfix logs the above message for domains different from +"localhost", and the sender cannot be changed to use complete domain +names in email addresses, then the system administrator should make +the backwards-compatible setting "<a href="postconf.5.html#append_dot_mydomain">append_dot_mydomain</a> = yes" permanent +in <a href="postconf.5.html">main.cf</a>: </p> + +<blockquote> +<pre> +# <b>postconf <a href="postconf.5.html#append_dot_mydomain">append_dot_mydomain</a>=yes</b> +# <b>postfix reload</b> +</pre> +</blockquote> + +</ul> + +<h2> <a name="chroot"> Using backwards-compatible default +setting chroot=y</a> </h2> + +<p> The <a href="master.5.html">master.cf</a> chroot default value has changed from "y" (yes) +to "n" (no). The new default avoids the need for copies of system +files under the Postfix queue directory. However, sites with strict +security requirements may want to keep the chroot feature enabled +after updating Postfix from an older version. The backwards-compatibility +safety net is designed allow the administrator to choose if they +want to keep the old behavior. </p> + +<p> As long as a <a href="master.5.html">master.cf</a> chroot field is left at its +implicit default value, and the <a href="postconf.5.html#compatibility_level">compatibility_level</a> setting +is less than 1, Postfix may log the following message while it +reads the <a href="master.5.html">master.cf</a> file: </p> + +<blockquote> +<pre> +postfix/master[27664]: /etc/postfix/<a href="master.5.html">master.cf</a>: line 72: using + backwards-compatible default setting chroot=y +</pre> +</blockquote> + +<p> If this service should remain chrooted, then the system +administrator should make the backwards-compatible setting "chroot += y" permanent in <a href="master.5.html">master.cf</a>. For example, to update the chroot +setting for the "smtp inet" service: </p> + +<blockquote> +<pre> +# <b>postconf -F smtp/inet/chroot=y</b> +# <b>postfix reload</b> +</pre> +</blockquote> + +<h2> <a name="relay_restrictions"> Using backwards-compatible default +setting smtpd_relay_restrictions = (empty)</a> </h2> + +<p> The <a href="postconf.5.html#smtpd_relay_restrictions">smtpd_relay_restrictions</a> feature was introduced with Postfix +version 2.10, as a safety mechanism for configuration errors in +<a href="postconf.5.html#smtpd_recipient_restrictions">smtpd_recipient_restrictions</a> that could make Postfix an open relay. +</p> + +<p> The <a href="postconf.5.html#smtpd_relay_restrictions">smtpd_relay_restrictions</a> implicit default setting forbids +mail to remote destinations from clients that don't match +<a href="postconf.5.html#permit_mynetworks">permit_mynetworks</a> or <a href="postconf.5.html#permit_sasl_authenticated">permit_sasl_authenticated</a>. This could result +in unexpected 'Relay access denied' errors after Postfix is updated +from an older Postfix version. The backwards-compatibility safety +net is designed to prevent such surprises. </p> + +<p> When the <a href="postconf.5.html#compatibility_level">compatibility_level</a> less than 1, and the +<a href="postconf.5.html#smtpd_relay_restrictions">smtpd_relay_restrictions</a> parameter is left at its implicit default +setting, Postfix may log the following message: </p> + +<blockquote> +<pre> +postfix/smtpd[38463]: using backwards-compatible default setting + "<a href="postconf.5.html#smtpd_relay_restrictions">smtpd_relay_restrictions</a> = (empty)" to avoid "Relay access + denied" error for recipient "user@example.com" from client + "host.example.net[10.0.0.2]" +</pre> +</blockquote> + +<p> If this request should not be blocked, then the system +administrator should make the backwards-compatible setting +"<a href="postconf.5.html#smtpd_relay_restrictions">smtpd_relay_restrictions</a>=" (i.e. empty) permanent in <a href="postconf.5.html">main.cf</a>: + +<blockquote> +<pre> +# <b>postconf <a href="postconf.5.html#smtpd_relay_restrictions">smtpd_relay_restrictions</a>=</b> +# <b>postfix reload</b> +</pre> +</blockquote> + +<h2> <a name="mynetworks_style"> Using backwards-compatible default +setting mynetworks_style=subnet</a> </h2> + +<p> The <a href="postconf.5.html#mynetworks_style">mynetworks_style</a> default value has changed from "subnet" +to "host". This parameter is used to implement the "<a href="postconf.5.html#permit_mynetworks">permit_mynetworks</a>" +feature. The change could in unexpected 'access denied' errors after +Postfix is updated from an older version. The backwards-compatibility +safety net is designed to prevent such surprises. </p> + +<p> As long as the <a href="postconf.5.html#mynetworks">mynetworks</a> and <a href="postconf.5.html#mynetworks_style">mynetworks_style</a> parameters are +left at their implicit default values, and the <a href="postconf.5.html#compatibility_level">compatibility_level</a> +setting is less than 2, the Postfix SMTP server may log one of the +following messages: </p> + +<blockquote> +<pre> +postfix/smtpd[17375]: using backwards-compatible default setting + <a href="postconf.5.html#mynetworks_style">mynetworks_style</a>=subnet to permit request from client + "foo.example.com[10.1.1.1]" +</pre> +</blockquote> + +<blockquote> +<pre> +postfix/postscreen[24982]: using backwards-compatible default + setting <a href="postconf.5.html#mynetworks_style">mynetworks_style</a>=subnet to permit request from client + "10.1.1.1" +</pre> +</blockquote> + +<p> If the client request should not be rejected, then the system +administrator should make the backwards-compatible setting +"<a href="postconf.5.html#mynetworks_style">mynetworks_style</a> = subnet" permanent in <a href="postconf.5.html">main.cf</a>: </p> + +<blockquote> +<pre> +# <b>postconf <a href="postconf.5.html#mynetworks_style">mynetworks_style</a>=subnet</b> +# <b>postfix reload</b> +</pre> +</blockquote> + +<h2><a name="relay_domains"> Using backwards-compatible default +setting relay_domains=$mydestination </a> </h2> + +<p> The <a href="postconf.5.html#relay_domains">relay_domains</a> default value has changed from "$<a href="postconf.5.html#mydestination">mydestination</a>" +to the empty value. This could result in unexpected 'Relay access +denied' errors or ETRN errors after Postfix is updated from an older +version. The backwards-compatibility safety net is designed to +prevent such surprises. </p> + +<p> As long as the <a href="postconf.5.html#relay_domains">relay_domains</a> parameter is left at its implicit +default value, and the <a href="postconf.5.html#compatibility_level">compatibility_level</a> setting is less than 2, +Postfix may log one of the following messages. </p> + +<ul> + +<li> <p> Messages about accepting mail for a remote domain:</p> + +<blockquote> +<pre> +postfix/smtpd[19052]: using backwards-compatible default setting + <a href="postconf.5.html#relay_domains">relay_domains</a>=$<a href="postconf.5.html#mydestination">mydestination</a> to accept mail for domain + "foo.example.com" +</pre> +</blockquote> + +<blockquote> +<pre> +postfix/smtpd[19052]: using backwards-compatible default setting + <a href="postconf.5.html#relay_domains">relay_domains</a>=$<a href="postconf.5.html#mydestination">mydestination</a> to accept mail for address + "user@foo.example.com" +</pre> +</blockquote> + +<li> <p> Messages about providing ETRN service for a remote domain:</p> + +<blockquote> +<pre> +postfix/smtpd[19138]: using backwards-compatible default setting + <a href="postconf.5.html#relay_domains">relay_domains</a>=$<a href="postconf.5.html#mydestination">mydestination</a> to flush mail for domain + "bar.example.com" +</pre> +</blockquote> + +<blockquote> +<pre> +postfix/smtp[13945]: using backwards-compatible default setting + <a href="postconf.5.html#relay_domains">relay_domains</a>=$<a href="postconf.5.html#mydestination">mydestination</a> to update fast-flush logfile for + domain "bar.example.com" +</pre> +</blockquote> + +</ul> + +<p> If Postfix should continue to accept mail for that domain or +continue to provide ETRN service for that domain, then the system +administrator should make the backwards-compatible setting +"<a href="postconf.5.html#relay_domains">relay_domains</a> = $<a href="postconf.5.html#mydestination">mydestination</a>" permanent in <a href="postconf.5.html">main.cf</a>: </p> + +<blockquote> +<pre> +# <b>postconf '<a href="postconf.5.html#relay_domains">relay_domains</a>=$<a href="postconf.5.html#mydestination">mydestination</a>'</b> +# <b>postfix reload</b> +</pre> +</blockquote> + +<p> Note: quotes are required as indicated above. </p> + +<p> Instead of $<a href="postconf.5.html#mydestination">mydestination</a>, it may be better to specify an +explicit list of domain names. </p> + +<h2> <a name="smtputf8_enable"> Using backwards-compatible default +setting smtputf8_enable=no</a> </h2> + +<p> The <a href="postconf.5.html#smtputf8_enable">smtputf8_enable</a> default value has changed from "no" to "yes. +With the new "yes" setting, the Postfix SMTP server rejects non-ASCII +addresses from clients that don't request SMTPUTF8 support, after +Postfix is updated from an older version. The backwards-compatibility +safety net is designed to prevent such surprises. </p> + +<p> As long as the <a href="postconf.5.html#smtputf8_enable">smtputf8_enable</a> parameter is left at its implicit +default value, and the <a href="postconf.5.html#compatibility_level">compatibility_level</a> setting is +less than 1, Postfix logs a warning each time an SMTP command uses a +non-ASCII address localpart without requesting SMTPUTF8 support: </p> + +<blockquote> +<pre> +postfix/smtpd[27560]: using backwards-compatible default setting + <a href="postconf.5.html#smtputf8_enable">smtputf8_enable</a>=no to accept non-ASCII sender address + "??@example.org" from localhost[127.0.0.1] +</pre> +</blockquote> + +<blockquote> +<pre> +postfix/smtpd[27560]: using backwards-compatible default setting + <a href="postconf.5.html#smtputf8_enable">smtputf8_enable</a>=no to accept non-ASCII recipient address + "??@example.com" from localhost[127.0.0.1] +</pre> +</blockquote> + +<p> If the address should not be rejected, and the client cannot +be updated to use SMTPUTF8, then the system administrator should +make the backwards-compatible setting "<a href="postconf.5.html#smtputf8_enable">smtputf8_enable</a> = no" permanent +in <a href="postconf.5.html">main.cf</a>: + +<blockquote> +<pre> +# <b>postconf <a href="postconf.5.html#smtputf8_enable">smtputf8_enable</a>=no</b> +# <b>postfix reload</b> +</pre> +</blockquote> + +<h2> <a name="turnoff">Turning off the backwards-compatibility safety net</a> </h2> + +<p> Backwards compatibility is turned off by updating the +<a href="postconf.5.html#compatibility_level">compatibility_level</a> setting in <a href="postconf.5.html">main.cf</a>. </p> + +<blockquote> +<pre> +# <b>postconf <a href="postconf.5.html#compatibility_level">compatibility_level</a>=<i>N</i></b> +# <b>postfix reload</b> +</pre> +</blockquote> + +<p> For <i>N</i> specify the number that is logged in your <a href="postfix.1.html">postfix(1)</a> +warning message: </p> + +<blockquote> +<pre> +warning: To disable backwards compatibility use "postconf <a href="postconf.5.html#compatibility_level">compatibility_level</a>=<i>N</i>" and "postfix reload" +</pre> +</blockquote> + +<p> Sites that don't care about backwards compatibility may set +"<a href="postconf.5.html#compatibility_level">compatibility_level</a> = 9999" at their own risk. </p> + +</body> + +</html> |