How to get and install Comodo free ssl sertificate on linux.
yum install mod_ssl openssl
openssl req -nodes -newkey rsa:2048 -keyout domain.key -out domain.csr -subj "/C=GB/ST=Yorks/L=York/O=Kodilo Ltd./OU=IT/CN=domain.com"
Register Comodo account and follow instructions.
In the end get two certificate files: domain.ca-bundle and domain.crt, place it to /etc/ssl/certs folder.
In /etc/httpd/conf.d/ssl.conf edit or create new VirtualHost on port 443 and add following settings to it:
SSLEngine on
SSLCertificateKeyFile /etc/ssl/domain.key
SSLCertificateFile /etc/ssl/certs/domain.crt
SSLCertificateChainFile /etc/ssl/certs/domain.ca-bundle