How to renew the SSL certificates for dovecot and postfix

Make a backup of the existing SSL key and certificate file

cd /etc/pki/dovecot
cp -a certs/dovecot.pem certs/dovecot.pem.old
cp -a private/dovecot.pem private/dovecot.pem.old

Create the new SSL certificate for two years:

openssl genrsa -out private/dovecot.pem 1024
openssl req -new -x509 -key private/dovecot.pem -out certs/dovecot.pem -days 730

Restart Dovecot and Postfix

sudo systemctl 
Read more

fail2ban filters – custom rules using regexp


fail2Ban is a very handy tool to prevent a lot of unwanted traffic from consuming bandwidth on your servers. It’s a minimal and relatively simple IDS Type Tool that comes with some predefined filters to automatically lockout potentially dangerous or bandwidth-consuming type attacks.

1. creating a custom filter

Read more