How to Set Up Multiple SSLs on One IP With Nginx

Reading Time: 6 minutes

With the shortage of available address space in IPv4, IPs are becoming increasingly difficult to come by, and in some cases, increasingly expensive. However, in most instances, this is not a drawback. Servers are perfectly capable of hosting multiple websites on one IP address, as they have for years.

But, there was a time when using an SSL certificate to secure traffic to your site required having a separate IPv4 address for each secured domain. This is not because SSLs were bound to IPs, or even to servers, but because the request for SSL certificate information did not specify what domain was being loaded, and thus the server was forced to respond with only one certificate. A name mismatch caused an insecure certificate warning, and therefore, a server owner was required to have unique IPs for all SSL hosts.

Luckily, IPv4 limitations have brought new technologies and usability to the forefront, most notably, Server Name Indication (SNI).


Why Do I Need an SSL?

Secure Socket Layer (SSL) certificates allow two-way encrypted communication between a client and a server. This allows any data protection from prying eyes, including sensitive information like credit card numbers or passwords. SSLs are optionally signed by a well-known, third-party signing authority, such as GlobalSign. The most common use of such certificates are to secure web traffic over HTTPS.

When browsing an HTTPS site, rather than displaying a positive indicator, modern browsers show a negative indicator for a site that is not using an SSL. So, websites that don’t have an SSL will have a red flag right off the bat for any new visitors. Sites that want to maintain reputation are therefore forced to get an SSL.

Luckily, it is so easy to get and install an SSL, even for free, that this is reduced to a basic formality. We’ll cover the specifics of this below.


What is SNI?

Server Name Indication is a browser and web server capability in which an HTTPS request includes an extra header, server_name, to which the server can respond with the appropriate SSL certificate. This allows a single IP address to host hundreds or thousands of domains, each with their own SSL!

SNI technology is available on all modern browsers and web server software, so some 98+% of web users, according to W3, will be able to support it.


Pre-Flight Check

We’ll be working on a CentOS 7 server that uses Nginx and PHP-FPM to host websites without any control panel (cPanel, Plesk, etc.). This is commonly referred to as a “LEMP” stack, which substitutes Nginx for Apache in the “LAMP” stack. These instructions will be similar to most other flavors of Linux, though the installation of Let’s Encrypt for Ubuntu 18.04 will be different. I’ll include side-by-side instructions for both CentOS 7 and Ubuntu 18.04.

For the remainder of the instructions, we’ll assume you have Nginx installed and set up to host multiple websites, including firewall configuration to open necessary ports (80 and 443). We are connected over SSH to a shell on our server as root.

If you have SSLs for each domain, but they are just not yet installed, you should use Step 3a to add them manually. If you do not have SSLs and would like to use the free Let’s Encrypt service to order and automatically configure them, you should use Step 3b.


Step 1: Enabling SNI in Nginx

Our first step is already complete! Modern repository versions of Nginx will be compiled with OpenSSL support to server SNI information by default. We can confirm this on the command line with:

nginx -V

This will output a bunch of text, but we are interested in just this line:

TLS SNI support enabled

If you do not have a line like this one, then Nginx will have to be re-compiled manually to include this support. This would be a very rare instance, such as in an outdated version of Nginx, one already manually compiled from source with a different OpenSSL library. The Nginx version installed by the CentOS 7 EPEL repository (1.12.2) and the one included with Ubuntu 18.04 (1.14.0) will support SNI.

Step 2: Configuring Nginx Virtual Hosts

Since you have already set up more than one domain in Nginx, you likely have server configuration blocks set up for each site in a separate file. Just in case you don’t, let’s first ensure that our domains are set up for non-SSL traffic. If they are, you can skip this step. We’ll be working on and

vim /etc/nginx/sites-available/

If you don’t happen to have sites-enabled or sites-available folders, and you want to use them, you can create /etc/nginx/sites-available and /etc/nginx/sites-enabled with the mkdir command. Afterward,  inside /etc/nginx/nginx.conf, add this line anywhere inside the main http{} block (we recommend putting it right after the include line that talks about conf.d):

include /etc/nginx/sites-enabled/*;

Otherwise, you can make your configurations in /etc/nginx/conf.d/*.conf.

At the very least, insert the following options, replacing the document root with the real path to your site files, and adding any other variables you require for your sites:

server {
listen 80;
root /var/www/;

A similar file should be set up for, and any other domains you wish to host. Once these files are created, we can enable them with a symbolic link:

ln -s /etc/nginx/sites-available/ /etc/nginx/sites-enabled/

ln -s /etc/nginx/sites-available/ /etc/nginx/sites-enabled/

Now, we restart Nginx…

systemctl reload nginx

This reloads the configuration files without restarting the application. We can confirm that the two we just made are loaded using:

nginx -T

You should see your server_name line for both and

The listen line included in the server block above will allow the site to listen on any IP that is on the server. If you would like to specify an IP instead, you can use the IP:port format instead, like this:

server {

Step 3a: Add Existing SSLs to Nginx Virtual Hosts

Now that we have valid running configurations, we can add the SSLs we have for these domains as new server blocks in Nginx. First, save your SSL certificate and the (private) key to a global folder on the server, with names that indicate the relevant domain. Let’s say that you chose the global folder of /etc/ssl/. Our names, in this case, will be /etc/ssl/ (which contains the certificate itself and any chain certificates from the signing authority), and /etc/ssl/, which contains the private key. Edit the configuration files we created:

vim /etc/nginx/sites-available/

Add a brand new server block underneath the end of the existing one (outside of the last curly brace) with the following information:

server {
listen 443;
root /var/www/;
ssl_certificate /etc/ssl/;
ssl_certificate_key /etc/ssl/;

Note the change of the listening port to 443 (for HTTPS) and the addition of the ssl_certificate and ssl_certificate_key lines. Instead of rewriting the whole block, you could copy the original server block and then add these extra lines, while changing the listen port. Save this file and reload the Nginx configuration.

systemctl reload nginx

We again confirm the change is in place using:

nginx -T

For some setups you’ll see two server_name lines each for and, one using port 80 and one using port 443. If you do, you can skip to Step 4, otherwise continue to the next step.

Step 3b: Install and Configure Let’s Encrypt

Let’s next set up the free SSL provider Let’s Encrypt to automatically sign certificates for all of the domains we just set up in Nginx. On Ubuntu 18.04, add the PPA and install the certificate scripts with aptitude:

add-apt-repository ppa:certbot/certbot

apt-get update

apt-get install certbot python-certbot-nginx

In CentOS 7, we install the EPEL repository and install the certificate helper from there.

yum install epel-release

yum install certbot python2-certbot-nginx

On both systems, we can now read the Nginx configuration and ask the Certbot to assign us some certificates.

certbot --nginx

This will ask you some questions about which domains you would like to use (you can leave the option blank to select all domains) and whether you would like Nginx to redirect traffic to your new SSL (we would!). After it finishes it’s signing process, Nginx should automatically reload its configuration, but in case it doesn’t, reload it manually:

systemctl reload nginx

You can now check the running configuration with:

nginx -T

You should now instead see two server_name lines each for and, one using port 80 and one using port 443.

Let’s Encrypt certificates are only valid for 90 days from issuance, so we want to ensure that they are automatically renewed. Edit the cron file for the root user by running:

crontab -e

The cron should look like this:

45 2 * * 3,6 certbot renew && systemctl reload nginx

Once you save this file, every Wednesday and Saturday at 2:45 AM, the certbot command will check for any needed renewals, automatically download and install the certs, followed by a reload of the Nginx configuration.

Step 4: Verify Installation and Validity

We should now check the validity of our SSLs and ensure that browsers see the certificates properly. Visit and type in your domain names to check the site’s SSL on your server. You should see four green checkmarks, indicatating SSL protection.

We hope you’ve enjoyed our tutorial on how to install SSLs on multiple sites within one server. Liquid Web customers have access to our support team 24/7.  We can help with signed SSL or ordering a new server for an easy transfer over to Liquid Web.

How to Setup Let’s Encrypt on Ubuntu 18.04

Reading Time: 3 minutes

Sites with SSL are needed more and more every day. It’s ubiquitious enforcement challenges website encryption and is even an effort that Google has taken up. Certbot and Let’s Encrypt are popular solutions for big and small businesses alike because of the ease of implementation.  Certbot is a software client that can be downloaded on a server, like our Ubuntu 18.04, to install and auto-renew SSLs. It obtains these SSLs by working with the well known SSL provider called Let’s Encrypt. In this tutorial, we’ll be showing you a swift way of getting HTTPS enabled on your site.  Let’s get started! Continue reading “How to Setup Let’s Encrypt on Ubuntu 18.04”

How to Use Let’s Encrypt with Cloudflare

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Cloudflare is an excellent and well-known content delivery network. A CDN can increase site speed by utilizing Cloudflare’s global caching network to deliver content closer to a visitor’s location. You can also easily attach Cloudflare as an add-on product to your existing Liquid Web server, but there are some configurations to consider. Continue reading “How to Use Let’s Encrypt with Cloudflare”

Enabling Let’s Encrypt for AutoSSL on WHM based Servers

Reading Time: 2 minutes

With the recent release of cPanel & WHM version 58 there has been the addition of an AutoSSL feature, this tool can be used to automatically provide Domain Validated SSLs for domains on your WHM & cPanel servers.

Initially this feature was released with support provided for only cPanel (powered by Comodo) based SSL certificates, with the plans to support more providers as things progressed. As of now, cPanel & WHM servers running version 58.0.17, and above, can now also use Let’s Encrypt as an SSL provider. More information on Let’s Encrypt can be found here. Continue reading “Enabling Let’s Encrypt for AutoSSL on WHM based Servers”

Transfer an SSL to Ubuntu 16.04 or CentOS 7

Reading Time: 7 minutes

SSL certificates have become a de facto part of every website. If you don’t yet have an SSL on your site to encrypt data, you should. Rather than showing an extra layer of security on sites protected by SSL, modern browsers instead now display a warning when a website does not have an SSL, essentially requiring sites to maintain their positive image.

When moving from one server to another, what needs to happen to your SSL to maintain your secure status? We’ll cover the basics for transferring traditional and Let’s Encrypt SSLs to Ubuntu 16.04 and CentOS 7.

This article will address SSLs in Apache specifically, but the same concepts apply to any service that supports SSL encryption.

Can SSLs be transferred between servers?

Continue reading “Transfer an SSL to Ubuntu 16.04 or CentOS 7”

How To Generate and Renew Let’s Encrypt SSL Certificates in Plesk 12.5

Reading Time: 3 minutes

Let’s Encrypt is a free, automated, and open certificate authority from the Internet Security Research Group (ISRG). It enables anyone to install a free trusted SSL certificate on their website and benefit from the enhanced security an encrypted connection provides. Unlike a self-signed SSL certificate, which also is free and secure (but not verified), a Let’s Encrypt certificate is recognized as fully verified and will display the padlock icon in the address bar of modern browsers.

Beginning with version 12.5, Plesk provides access to both a plugin which interfaces with the Let’s Encrypt CLI client and an extension for use within Plesk. Please note that Plesk’s support for Let’s Encrypt applies to some Linux distributions as well as Windows, and while these instructions may also apply to a Linux server running CentOS 6 or higher, additional configuration beyond the scope of this article may be necessary. Continue reading “How To Generate and Renew Let’s Encrypt SSL Certificates in Plesk 12.5”