How to configure Nginx with Let’s Encrypt on CentOS 7

How do I secure my Nginx web server with Let’s Encrypt free ssl certificate on my CentOS 7 or RHEL 7 server? How to configure Nginx with Let’s Encrypt on CentOS 7 server?

Let’s Encrypt is a free, automated, and open certificate authority for your website or any other projects. This page shows how to use Let’s Encrypt to install a free SSL certificate for Nginx web server. You will learn how to properly deploy Diffie-Hellman on your server to get SSL labs A+ score on a CentOS/RHEL 7.

How to secure Nginx with Let’s Encrypt on CentOS 7

Our sample setup is as follows:

How to secure Nginx with Let’s Encrypt on CentOS 7

The procedure is as follows to obtaining an SSL certificate:

  1. Get software:
    git clone
  2. Create /.well-known/acme-challenge/ directory:
    mkdir -p /var/www/html/.well-known/acme-challenge/
  3. Obtaining an SSL certificate your domain: --issue -w /DocumentRootPath/ -d your-domain
  4. Configure TLS/SSL on Nginx:
    vi /etc/nginx/sites-available/default
  5. Setup cron job setup for auto renewal
  6. Open port 443 (HTTPS):
    sudo firewall-cmd --add-service=https

Let us see how to install client and use it on a CentOS/RHEL 7 to get an SSL certificate from Let’s Encrypt.

Step 1 – Install the required software

Install the git, wget, curl and bc packages with the yum command:
$ sudo yum install git bc wget curl

Step 2 – Install Let’s Encrypt client

Clone the repo:
$ cd /tmp/
$ git clone

Install client on to your system, run:
$ cd
$ sudo -i
# ./ --install

After install, you must close current terminal and reopen again to make the alias take effect. Or simply type the following source command:
$ sudo source ~/.bashrc

Step 3 – Create acme-challenge directory

Type the following mkdir command. Make sure you set D to actual DocumentRoot path as per your needs:
# D=/usr/share/nginx/html
# mkdir -vp ${D}/.well-known/acme-challenge/
###---[ NOTE: Adjust permission as per your setup ]---###
# chown -R nginx:nginx ${D}/.well-known/acme-challenge/
# chmod -R 0555 ${D}/.well-known/acme-challenge/

Also create directory to store SSL certificate:
# mkdir -p /etc/nginx/ssl/

Step 4 – Create dhparams.pem file

Run openssl command:
# cd /etc/nginx/ssl/
# openssl dhparam -out dhparams.pem -dsaparam 4096

Step 5 – Obtain a certificate for domain

Issue a certificate for your domain: --issue -w /path/to/www/htmlRoot/ -d -k 2048
sudo --issue -w /usr/local/nginx/html -d -k 2048

Step 6 – Configure Nginx

You just successfully requested an SSL Certificate from Let’s Encrypt for your CentOS 7 or RHEL 7 server. It is time to configure it. Edit default.ssl.conf:
$ sudo vi /etc/nginx/conf.d/default.ssl.conf
Append the following config:

server {
    #------- Start SSL config with http2 support ----#
    listen http2;
    ssl on;
    ssl_certificate /etc/nginx/ssl/;
    ssl_certificate_key /etc/nginx/ssl/;
    ssl_session_timeout 30m;
    ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
    ssl_session_cache shared:SSL:10m;
    ssl_dhparam /etc/nginx/ssl/;
    ssl_prefer_server_ciphers on;
    ## Improves TTFB by using a smaller SSL buffer than the nginx default
    ssl_buffer_size 8k;
    ## Enables OCSP stapling
    ssl_stapling on;
    ssl_stapling_verify on;
    ## Send header to tell the browser to prefer https to http traffic
    add_header Strict-Transport-Security max-age=31536000;
    ## SSL logs ##
    access_log /var/log/nginx/ssl_access.log;
    error_log /var/log/nginx/ssl_error.log;
    #-------- END SSL config -------##
    # Add rest of your config below like document root, php and more ##
    location / {
        root   /usr/share/nginx/html;
        index  index.html index.htm;
    # Allow php apps
    location ~ \.php$ {
        root /usr/share/nginx/html;
        fastcgi_index  index.php;
        include        fastcgi_params;
        fastcgi_param  SCRIPT_FILENAME  $document_root$fastcgi_script_name;
## END SSL ######

Save and close the file in vi/vim text editor.

Step 7 – Install certificate

Install the issued cert to nginx server:
# --installcert -d \
--keypath /etc/nginx/ssl/ \
--fullchainpath /etc/nginx/ssl/ \
--reloadcmd 'systemctl reload nginx'

Make sure port os open with the ss command or netstat command:
# ss -tulpn

Step 8 – Firewall configuration

You need to open port 443 (HTTPS) on your server so that clients can connect it. Update the rules as follows:
$ sudo firewall-cmd --add-service=https
$ sudo firewall-cmd --runtime-to-permanent

Step 9 – Test it

Fire a web browser and type your domain such as:
Test it with SSLlabs test site:

Step 10 – commands

List all certificates:
# --list
Renew a cert for domain named
# --renew -d
Please note that a cron job will try to do renewal a certificate for you too. This is installed by default as follows (no action required on your part). To see job run:
# crontab -l
Sample outputs:

8 0 * * * "/root/"/ --cron --home "/root/" > /dev/null

Upgrade client:
# --upgrade
Getting help:
# --help | more


You learned how to install and set up Let’s Encrypt TLS/SSL certificate on your CentOS Linux 7 server. See project home page here for more information.

This entry is 3 of 3 in the Linux, Nginx, MySQL, PHP (LEMP) Stack for CentOS/RHEL 7 Tutorial series. Keep reading the rest of the series:
  1. How to install and use Nginx on CentOS 7 / RHEL 7
  2. How to install PHP 7.2 on CentOS 7/RHEL 7
  3. How to configure Nginx with Let's Encrypt on CentOS 7

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