Let’s Encrypt is a new Certificate Authority: It’s free, automated, and open.

Certbot, previously the Let's Encrypt Client, is EFF's tool to obtain certs from Let's Encrypt, and (optionally) auto-enable HTTPS on your server. It can also act as a client for any other CA that uses the ACME protocol.

Certbot Official site:
Get Certbot from:


CentOS 6

# sudo yum install epel-release
$ wget
$ chmod a+x certbot-auto

CentOS 7

# yum install epel-release
# yum install certbot


$ certbot[-auto] certonly
$ certbot[-auto] certonly --standalone -d -d


# certbot[-auto] renew [--dry-run] [--quiet]