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You can use Let's encrypt certificates to secure communication with your e-mail server.

After you generate certificate for your mail server:

certbot-auto certonly --apache --non-interactive --agree-tos \
--email me@mydomian -d mail.jaqb.gda.pl

they have to be copied to new location because Postfix/CyrusIMAP cannot read them, the /etc/letsencrypt/live directory can be read only by root.

The solution is simple. I've copied them into /etc/postfix directory and change group to mail:

cp /etc/letsencrypt/live/mail.jaqb.gda.pl/cert.pem \
                                      /etc/postfix/cert.pem
cp /etc/letsencrypt/live/mail.jaqb.gda.pl/privkey.pem \
                                      /etc/postfix/privkey.pem
cp /etc/letsencrypt/live/mail.jaqb.gda.pl/fullchain.pem \
                                      /etc/postfix/fullchain.pem

chgrp mail /etc/postfix/cert.pem /etc/postfix/privkey.pem \
/etc/postfix/fullchain.pem 

I've added this commands to /etc/cron.monthly/letsencrypt-auto.bash file (from my last post).

Of course you have to set that appropriate options, at least in /etc/postfix/main.cf:

smtpd_tls_cert_file = /etc/postfix/cert.pem
smtpd_tls_key_file = /etc/postfix/privkey.pem
smtpd_tls_CAfile = /etc/postfix/fullchain.pem

and in /etc/imapd.conf:

tls_cert_file: /etc/postfix/cert.pem
tls_key_file: /etc/postfix/privkey.pem
tls_ca_file: /etc/postfix/fullchain.pem

After restart:

/etc/init.d/postfix restart
/etc/init.d/cyrus-imapd restart

everything should work. Good luck!

If you want to create a certificate you should download certbot-auto and install them in your system:

wget "https://dl.eff.org/certbot-auto"
mv certbot-auto /usr/local/sbin/
chmod u+x /usr/local/sbin/certbot-auto

Then you can request your first (test) certificate:

certbot-auto certonly --test-cert --apache \
--non-interactive --agree-tos --email me@mydomain.com \
-d www.jaqb.gda.pl

If you want to recreate certificate after tests you have to delete them, and then create again (without --test-cert option)

certbot-auto delete -d www.jaqb.gda.pl
certbot-auto certonly --apache --non-interactive  --agree-tos \
--email me@mydomain.com -d www.jaqb.gda.pl

Of course you can obtain more than one certificate:

certbot-auto certonly --apache --non-interactive  --agree-tos \
--email me@mydomain.com -d dev.jaqb.gda.pl

All certificates are stored in /etc/letsencrypt/live directory.

The certificates are valid only for 3 months, but don't worry everything can be automated - I've added to cron (/etc/cron.monthly/letsencrypt-auto.bash):

#!/bin/bash

certbot-auto renew --apache --non-interactive --agree-tos \
--email me@mydomain.com

I hope it will work... ;-)

It's rather bypass, but works:

Excel 2007 - Password Removal:

Create backup of password-protected excel file.
Change the file extension to .zip from .xlsx.
Now extract the whole content of zip file.
Search for xml format of targeted sheet. You will find it in ‘xl -> worksheets’ directory.
Open the xml file of targeted sheet in xml editor.
Now search for ‘sheetProtection’ word in that xml file and remove it.
Save this edited xml file and replace it with old xml file in zip files.
Now change the extension from .zip to .xlsx.

Just my blog...

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