How to Check the Expiration Date of Your SSL Certificate

In today’s digital age, securing your website is essential to protecting sensitive information,
ensuring trust, and complying with industry regulations. One of the fundamental elements of website security
is the SSL (Secure Sockets Layer) certificate. But like everything in the cyber world, SSL certificates
are not permanent fixtures; they come with an expiration date. Missing the expiration of your SSL
certificate can result in severe consequences. Therefore, it’s crucial to know how to check this expiration date and manage your certificates accordingly.

This article will walk you through the various methods you can use to check the expiration date of your
SSL certificate effectively. We’ll cover everything from using web browsers, online tools, command
line interfaces, to automation techniques, ensuring that you never miss an expiration deadline again.

Understanding SSL Certificates

Before diving into how to check the expiration date, let’s first understand what an SSL certificate is
and why it’s critical for website security.

What is an SSL Certificate?

An SSL certificate is a digital certificate that authenticates a website’s identity and enables an
encrypted connection. In layman’s terms, it ensures that any data transmitted between the user’s
browser and the website is encrypted and secure. This is particularly important for websites that
handle sensitive information, such as e-commerce sites and online banking platforms.

Why Do SSL Certificates Expire?

Like passports or driver’s licenses, SSL certificates have a validity period. This duration can range
from a few months to a couple of years, depending on the issuing authority’s policies. Certificates are
designed to expire to ensure that encryption technologies are regularly updated and to reduce the risk
of a compromise. When an SSL certificate expires, the website can become vulnerable to attacks, and
visitors might receive warnings that the site is not secure.

Methods to Check SSL Certificate Expiration Date

Now that you understand the importance of SSL certificates, let’s delve into the different methods to
check their expiration dates. These methods cater to different levels of technical proficiency, so
you’re sure to find one that suits your needs.

Using Web Browsers

One of the easiest ways to check an SSL certificate’s expiration date is through modern web browsers.
Here’s how you can do it in some of the most commonly used browsers:

Google Chrome

• Open the website whose SSL certificate you want to check.
• Click on the padlock icon in the URL bar.
• Select “Certificate” or “View Certificate.”
• Check the “Valid from” section for the expiration date.

Mozilla Firefox

• Open the website.
• Click on the padlock icon in the URL bar.
• Click “More Information” and then “View Certificate.”
• Check the “Validity” section for the expiration date.

Microsoft Edge

• Navigate to the website.
• Click on the padlock icon in the URL bar.
• Select “Certificate (Valid)” to view more details.
• Look at the “Valid from” section for the expiration date.

Using Online Tools

If you want to check the SSL certificate expiration date without opening the website in your browser,
there are several online tools available for this purpose. These tools are simple to use and
provide additional details about the certificate.

SSLShopper

This tool allows you to check the SSL certificate expiration date by entering the domain name. Here’s
how you can use it:

• Go to the SSLShopper website.
• Enter the domain name of your website.
• Click “Check SSL.”
• Review the expiration date and other details provided.

SSL Labs by Qualys

SSL Labs provides an in-depth analysis of your SSL certificate. Follow these steps:

• Visit SSL Labs website.
• Enter your domain name in the provided field.
• Click “Submit.”
• Wait for the analysis to complete and review the expiration date under the “Certificate” section.

Using Command Line (Linux)

For more technically inclined readers, checking the expiration date of an SSL certificate can be done
via command line. This method is especially useful for system administrators managing servers.

Using OpenSSL

OpenSSL is a robust, full-featured toolkit for the Transport Layer Security (TLS) and Secure Sockets
Layer (SSL) protocols. It is widely used in various Linux distributions.

To check the expiration date of an SSL certificate using OpenSSL, execute the following steps:

1. Open your terminal.
2. Run the following command:

echo | openssl s_client -connect yourdomain.com:443 2>/dev/null | openssl x509 -noout -dates

This command connects to the specified domain and retrieves the SSL certificate, displaying its valid
start and end dates.

Using Certbot

Certbot is a popular tool for managing Let’s Encrypt certificates. If you use Let’s Encrypt for your
SSL certificates, Certbot can check their expiration dates.

1. Install Certbot if it’s not already installed.
2. Run the following command:

sudo certbot certificates

This command will list all the SSL certificates managed by Certbot, including their expiration dates.

Automating SSL Certificate Expiration Checks

While manual checks are useful, they can be cumbersome, especially if you manage multiple websites or
servers. Automation tools can help ensure that you receive timely notifications before any SSL
certificate expires.

Using Cron Jobs

For Unix-based systems, cron jobs are an excellent way to automate tasks. You can set up a cron job to
run a script that checks the SSL certificate expiration date and sends you an email notification
if the date is approaching.

1. Write a shell script to check the SSL certificate expiration date:

#!/bin/bash
    DOMAIN="yourdomain.com"
    EXPIRE_DATE=$(echo | openssl s_client -connect $DOMAIN:443 2>/dev/null | openssl x509 -noout -enddate | cut -d= -f2)
    EXPIRE_DATE_EPOCH=$(date -d "$EXPIRE_DATE" +%s)
    CURRENT_DATE_EPOCH=$(date +%s)
    DIFF=$(( ($EXPIRE_DATE_EPOCH - $CURRENT_DATE_EPOCH) / 86400 ))

    if [ "$DIFF" -lt 30 ]; then
        echo "The SSL certificate for $DOMAIN will expire in $DIFF days." | mail -s "SSL Certificate Expiry Alert" youremail@example.com
    fi

Setting Up the Cron Job

1. Open your crontab with the following command:

crontab -e

Add the following line to run the script daily:

0 0 * * * /path/to/your/script.sh

This line schedules the script to run at midnight every day. Adjust the path to your script as needed.

Using Monitoring Tools

Various monitoring tools offer SSL certificate expiration alerts as part of their service. These tools
provide a dashboard for monitoring multiple domains and can send notifications through email, SMS, or
other channels.

UptimeRobot

UptimeRobot is a popular monitoring service that includes SSL certificate expiration monitoring. To set
it up:

1. Sign up for an account at UptimeRobot.
2. Add a new monitor and select “SSL” as the monitor type.
3. Enter your domain and set the alert settings according to your preference.

StatusCake

StatusCake is another robust monitoring tool that includes SSL certificate expiration alerts. Follow
these steps to use it:

1. Create an account at StatusCake.
2. Add a new test and configure it for SSL monitoring.
3. Set up your notification preferences to receive alerts.

Conclusion

SSL certificates are vital for securing websites and building user trust. However, they come with the
responsibility of regular maintenance, including tracking their expiration dates. Missing an SSL
certificate expiration can result in security vulnerabilities and a loss of user trust.

By using the methods detailed in this guide—whether through web browsers, online tools, command line
interfaces, or automated solutions—you can effectively manage your SSL certificates and ensure your
website remains secure. Don’t let an expired SSL certificate catch you off guard; stay vigilant and
take proactive measures to maintain your website’s security.