Garak: Created page with "This page contain some usefull commands and tips for using Postfix. = Certificate problems = If postfix can't validate email certificiates mail log will be full of message l..."

2021-05-22T16:22:25Z

Created page with "This page contain some usefull commands and tips for using Postfix. = Certificate problems = If postfix can't validate email certificiates mail log will be full of message l..."

New page

This page contain some usefull commands and tips for using Postfix.

= Certificate problems =

If postfix can't validate email certificiates mail log will be full of message like these
<pre>
certificate verification failed for gmail-smtp-in.l.google.com[74.125.196.26]:25: untrusted issuer /C=US/O=Equifax/OU=Equifax Secure Certificate Authority
</pre>
Check if certificates are installed and updated in <code>/etc/ssl/certs/</code>, if they are set
path to them manually by adding line to <code>/etc/postfix/main.cf</code>.
<pre>
smtp_tls_CAfile = /etc/ssl/certs/ca-certificates.crt
</pre>

= Checking mail queue =
To check current mail queue use:
<code bash>
postqueue -p | tail -n 1 | cut -d' ' -f5
</code>

= Searching and restoring emails in SPAM folder =
Default spam folder is <code bash>/var/lib/amavis/virusmails</code>.

To find name of spam email containing KEYWORD:
<pre>
cd /var/lib/amavis/virusmails
find . -name "*spam*.gz" -exec zgrep -l 'KEYWORD' {} \;| cut -c 3-
</pre>

To copy spam to original recipient mailbox, EMAILNAME should be relative to spam folder.
<pre>
amavisd-release EMAILNAME
</pre>

To release found mail:
<pre>
find . -name "*spam*.gz" -exec zgrep -l 'KEYWORD' {} \;| cut -c 3- | xargs -L 1 amavisd-release
</pre>

= How to move Postfix mail queue =

This document describes how to move Postfix mail queue from one server to another without downtime.

* '''ServerA''' - server with queue we want to move
* '''ServerB''' - server with install working Postfix

Before start, check both ServerA and ServerB hold queue <code>/var/spool/postfix/hold</code>.
Any email in hold queue will be send. In case there are emails in hold that should not be send move them out of hold folder.

== ServerA ==
Move all waiting emails to hold queue.
<pre>
postsuper -h ALL
</pre>

Tar hold folder and copy it to ServerB.
<pre>
tar -zcvf postfixhold.tar.gz /var/spool/postfix/hold
scp postfixhold.tar.gz user@ServerB:/home/user/
</pre>

== ServerB ==
Untar to <code>/var/spool/postfix/hold</code>.
<pre>
tar -C / -zxvf postfixhold.tar.gz
</pre>

Number of added hold emails should increase queued emails (Protip: run this command before untaring hold emails)
<pre>
postqueue -p | tail -n 1 | cut -d' ' -f5
</pre>

Put emails from hold to deferred queue.
<pre>
postsuper -H ALL
</pre>
Manual recommends releasing emails near maximal wait time directly to active queue.
<pre>
postsuper -r ALL hold
</pre>

== ServerA ==
Now remove whole hold queue on ServerA.
<pre>
postsuper -d ALL hold
</pre>

= Log statistics =

One of tools for generating statistics from email logs is <code>Pflogsumm</code>.

Installation
<pre>
sudo curl -O http://jimsun.linxnet.com/downloads/pflogsumm-1.1.3.tar.gz
sudo tar -xzf pflogsumm-1.1.3.tar.gz
</pre>

Usage
<pre>
./pflogsumm.pl /var/log/email.log > report.txt
</pre>

= Getting message id =
Getting message id from mail where argo or bugweis is mentioned
<pre>
mailq | grep -v '^ *(' | awk 'BEGIN { RS = "" } { if ($0 ~ /(argo22\.)|(bugweis\.)/) print $1 }' | tr -d '*!'
</pre>

= Release multiple emails from hold =
Can be connected wtih 'Getting message id' command and output piped directly to postsuer.
-H - will read message ID from input.
<pre>
cat ouremails_ID.txt | postsuper -H -
</pre>

= Removing emails for whole domain =
First be sure you know what are you doing, this will DELETE most of emails in standard email directory!
Running script at wrong place can cripple the company!

Backup vhole email directory (/var/vmail/DOMAIN/).

Run following script, make sure initial change directory is set correctly
<pre>
cd /var/vmail/DOMAIN;
for DIR in `ls -l`; do rm -vf $DIR/Maildir/cur/*;rm -vf $DIR/Maildir/new/*;rm -vf $DIR/Maildir/.*/cur/*;rm -vf $DIR/Maildir/.*/new/*; done;
</pre>

ZhoubaWiki:PostfixTips - Revision history

Garak: Created page with "This page contain some usefull commands and tips for using Postfix. = Certificate problems = If postfix can't validate email certificiates mail log will be full of message l..."