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diff --git a/html/LINUX_README.html b/html/LINUX_README.html new file mode 100644 index 0000000..0d5b0ee --- /dev/null +++ b/html/LINUX_README.html @@ -0,0 +1,119 @@ +<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN" + "http://www.w3.org/TR/html4/loose.dtd"> + +<html> + +<head> + +<title>Postfix and Linux</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 and Linux</h1> + +<hr> + +<h2> Host lookup issues </h2> + +<p> By default Linux /etc/hosts lookups do not support multiple IP +addresses per hostname. This causes warnings from the Postfix SMTP +server that "hostname XXX does not resolve to address YYY", and is +especially a problem with hosts that have both IPv4 and IPv6 +addresses. To fix this, turn on support for multiple IP addresses: </p> + +<blockquote> +<pre> +/etc/host.conf: + ... + # We have machines with multiple IP addresses. + multi on + ... +</pre> +</blockquote> + +<p> Alternatively, specify the RESOLV_MULTI environment variable +in <a href="postconf.5.html">main.cf</a>: </p> + +<blockquote> +<pre> +/etc/postfix/<a href="postconf.5.html">main.cf</a>: + <a href="postconf.5.html#import_environment">import_environment</a> = MAIL_CONFIG MAIL_DEBUG MAIL_LOGTAG TZ XAUTHORITY DISPLAY LANG=C RESOLV_MULTI=on +</pre> +</blockquote> + +<h2>Berkeley DB issues</h2> + +<p> If you can't compile Postfix because the file "db.h" +isn't found, then you MUST install the Berkeley DB development +package (name: db???-devel-???) that matches your system library. +You can find out what is installed with the rpm command. For example: +</p> + +<blockquote> +<pre> +$ <b>rpm -qf /usr/lib/libdb.so</b> +db4-4.3.29-2 +</pre> +</blockquote> + +<p> This means that you need to install db4-devel-4.3.29-2 (on +some systems, specify "<b>rpm -qf /lib/libdb.so</b>" instead). </p> + +<p> DO NOT download some Berkeley DB version from the network. +Every Postfix program will dump core when it is built with a different +Berkeley DB version than the version that is used by the system +library routines. See the <a href="DB_README.html">DB_README</a> file for further information. +</p> + +<h2>Procmail issues</h2> + +<p> On RedHat Linux 7.1 and later <b>procmail</b> no longer has +permission +to write to the mail spool directory. Workaround: </p> + +<blockquote> +<pre> +# chmod 1777 /var/spool/mail +</pre> +</blockquote> + +<h2>Logging in a container</h2> + +<p> When running Postfix inside a container, you can use stdout +logging as described in <a href="MAILLOG_README.html">MAILLOG_README</a>. Alternatives: run syslogd +inside the container, or mount the host's syslog socket inside the +container. </p> + +<h2>Syslogd performance</h2> + +<p> LINUX <b>syslogd</b> uses synchronous writes by default. Because +of this, <b>syslogd</b> can actually use more system resources than +Postfix. To avoid such badness, disable synchronous mail logfile +writes by editing /etc/syslog.conf and by prepending a - to the +logfile name: </p> + +<blockquote> +<pre> +/etc/syslog.conf: + mail.* -/var/log/mail.log +</pre> +</blockquote> + +<p> Send a "<b>kill -HUP</b>" to the <b>syslogd</b> to make the +change effective. </p> + +<h2>Other logging performance issues</h2> + +<p> LINUX <b>systemd</b> intercepts all logging and enforces its +own rate limits before handing off requests to a backend such as +<b>rsyslogd</b> or <b>syslog-ng</b>. On a busy mail server this can +result in information loss. As a workaround, you can use Postfix's +built-in logging as described in <a href="MAILLOG_README.html">MAILLOG_README</a>. </p> + +</body> + +</html> |