How to Enable TLS 1.3 in Apache on CentOS 8

TLS 1.3 is a version of the Transport Layer Security (TLS) protocol that was published in 2018 as a proposed standard in RFC 8446. It offers security and performance improvements over its predecessors.

This guide will demonstrate how to enable TLS 1.3 using the Apache webserver on CentOS 8.

Requirements

• Vultr Cloud Compute (VC2) instance running CentOS 8.
• A valid domain name and properly configured A/AAAA/CNAME DNS records for your domain.
• A valid TLS certificate. We will get one from Let's Encrypt.
• Apache version 2.4.36 or greater.
• OpenSSL version 1.1.1 or greater.

Before you begin

Check the CentOS version.

cat /etc/centos-release
# CentOS Linux release 8.0.1905 (Core)

Create a new non-root user account with sudo access and switch to it.

useradd -c "John Doe" johndoe && passwd johndoe
usermod -aG wheel johndoe
su - johndoe

NOTE: Replace johndoe with your username.

Set up the timezone.

timedatectl list-timezones
sudo timedatectl set-timezone 'Region/City'

Ensure that your system is up to date.

sudo yum update

Install the needed packages.

sudo yum install -y socat git

Disable SELinux and Firewall.

sudo setenforce 0 ; sudo systemctl stop firewalld ; sudo systemctl disable firewalld

Install the acme.sh client and obtain a TLS certificate from Let's Encrypt

Install acme.sh.

sudo mkdir /etc/letsencrypt
git clone https://github.com/Neilpang/acme.sh.git
cd acme.sh 
sudo ./acme.sh --install --home /etc/letsencrypt --accountemail your_email@example.com
cd ~
source ~/.bashrc

Check the version.

/etc/letsencrypt/acme.sh --version
# v2.8.2

Obtain RSA and ECDSA certificates for your domain.

# RSA
sudo /etc/letsencrypt/acme.sh --issue --standalone -d example.com --ocsp-must-staple --keylength 2048
# ECC/ECDSA
sudo /etc/letsencrypt/acme.sh --issue --standalone -d example.com --ocsp-must-staple --keylength ec-256

NOTE: Replace example.com in commands with your domain name.

Create sensible directories to store your certs and keys in. We will use /etc/letsencrypt.

sudo mkdir -p /etc/letsencrypt/example.com
sudo mkdir -p /etc/letsencrypt/example.com_ecc

Install and copy certificates to /etc/letsencrypt.

# RSA
sudo /etc/letsencrypt/acme.sh --install-cert -d example.com --cert-file /etc/letsencrypt/example.com/cert.pem --key-file /etc/letsencrypt/example.com/private.key --fullchain-file /etc/letsencrypt/example.com/fullchain.pem 
# ECC/ECDSA
sudo /etc/letsencrypt/acme.sh --install-cert -d example.com --ecc --cert-file /etc/letsencrypt/example.com_ecc/cert.pem --key-file /etc/letsencrypt/example.com_ecc/private.key --fullchain-file /etc/letsencrypt/example.com_ecc/fullchain.pem

After running the above commands, your certificates and keys will be in the following locations:

• RSA: /etc/letsencrypt/example.com
• ECC/ECDSA: /etc/letsencrypt/example.com_ecc

Install Apache

Apache added support for TLS 1.3 in version 2.4.36. CentOS 8 system comes with Apache and OpenSSL that support TLS 1.3 out of the box, so there is no need to build a custom version.

Download and install the latest 2.4 version of Apache and its module for SSL via the yum package manager.

sudo yum install -y httpd mod_ssl

Check the version.

sudo httpd -v
# Server version: Apache/2.4.37 (centos)
# Server built:   Jul  30 2019 19:56:12

Start and enable Apache.

sudo systemctl start httpd.service
sudo systemctl enable httpd.service

Configure Apache for TLS 1.3

Now that we have successfully installed Apache, we are ready to configure it to start using TLS 1.3 on our server.

Run sudo vim /etc/httpd/conf.d/example.com.conf, and populate the file with the following basic configuration.

<IfModule mod_ssl.c>
  <VirtualHost *:443>
    ServerName example.com

    SSLEngine on
    SSLProtocol all -SSLv2 -SSLv3

    # RSA
    SSLCertificateFile "/etc/letsencrypt/example.com/fullchain.pem"
    SSLCertificateKeyFile "/etc/letsencrypt/example.com/private.key"
    # ECC
    SSLCertificateFile "/etc/letsencrypt/example.com_ecc/fullchain.pem"
    SSLCertificateKeyFile "/etc/letsencrypt/example.com_ecc/private.key"

  </VirtualHost>
</IfModule>

Save the file and exit with Colon+W+Q.

Check the configuration.

sudo apachectl configtest

Reload Apache to activate the new configuration.

sudo systemctl reload httpd.service

Open your site via HTTPS protocol in your web browser. To verify TLS 1.3, you can use browser dev tools or SSL Labs service. The screenshots below show Chrome's security tab with TLS 1.3 in action.

You have successfully enabled TLS 1.3 in Apache on your CentOS 8 server. The final version of TLS 1.3 was defined in August 2018, so there’s no better time to start adopting this new technology.