[root@centos ~]# cd /etc/pki/tls/certs/ [root@centos certs]# openssl req -new -x509 -days 3650 -key server.key -out mail.crt You are about to be asked to enter information that will be incorporated into your certificate request. What you are about to enter is what is called a Distinguished Name or a DN. There are quite a few fields but you can leave some blank For some fields there will be a defau