
When it comes to online security, OCSP stapling is a crucial technology that enhances both the speed and privacy of SSL/TLS connections. By leveraging it, websites can deliver certificate information more efficiently, improving both website performance and user experience.
In this article, we’ll explore what OCSP stapling is, it’s benefits, how it works, and why it has become an essential part of SSL optimization.
Table of Contents
- What Is OCSP Stapling?
- Why Was OCSP Stapling Developed?
- How Does OCSP Stapling Work?
- Key Benefits of OCSP Stapling
- Difference Between OCSP and OCSP Stapling
- Alternatives to OCSP Stapling: OCSP Must-Staple
- Cons of OCSP Stapling
- How to Enable OCSP Stapling?

What Is OCSP Stapling?
OCSP stapling is an advanced feature of SSL/TLS protocols that allows a web server to deliver an OCSP (Online Certificate Status Protocol) response directly to clients, such as web browsers, during the SSL handshake. Traditionally, web clients would query the Certificate Authority (CA) directly to verify the status of a site’s SSL certificate. However, OCSP stapling changes this process by allowing the server to “staple” a recent OCSP response to its SSL handshake, removing the need for the client to interact with the CA.
The OCSP protocol itself is designed to ensure that SSL certificates are still valid and haven’t been revoked by providing status updates via an OCSP responder. It is acting as an alternative to the traditional certificate revocation list for checking validity. By enabling OCSP stapling, website owners help to minimize the need for external requests, offering a faster and more private SSL verification process.
Why Was OCSP Stapling Developed?
OCSP stapling was introduced to address several issues with traditional OCSP checks, primarily latency and privacy concerns, and identifying revoked certificates efficiently.
With the traditional OCSP approach, every time a client (like a web browser) needed to verify an SSL certificate, it would have to send OCSP queries to the Certificate Authority to confirm the certificate’s validity. This direct query often leads to slower loading times since the browser must wait for a response from an external server. Additionally, direct OCSP requests expose the client’s activity to the CA, creating a privacy risk.
OCSP stapling was developed to solve these issues by allowing the web server itself to obtain and cache an OCSP response. This way, the server can deliver a valid OCSP response directly to clients without the need for separate verification steps, cutting down latency and protecting client privacy.
How Does OCSP Stapling Work?
The process is simple yet effective. Here’s a step-by-step explanation:
- Server Request: The web server periodically requests an OCSP response from the Certificate Authority. This response indicates the certificate’s revocation status and confirms its validity.
- Caching the Response: The server caches this OCSP response, allowing it to be used multiple times within a certain period (typically 24 hours). This cached response is what the server will later provide to connecting clients.
- Stapling the Response: When a client attempts to establish an SSL connection, the server includes the cached OCSP response as part of the SSL handshake. This stapled response confirms to the client that the SSL certificate is still valid, without requiring an additional CA request.
- Client Verification: The client (e.g., a web browser) verifies the stapled OCSP response during the SSL handshake. If the response is valid and recent, the client completes the connection without needing to check with the CA directly.
By stapling the OCSP response, the server can reduce latency and improve SSL handshake speed, making the connection both faster and more secure.
Key Benefits of OCSP Stapling
Implementing it offers several benefits for website performance and user privacy:
- Speed and Latency Reduction: By providing the OCSP response directly, the server eliminates the need for a separate request to the CA, which reduces latency and speeds up SSL handshakes.
- Enhanced User Privacy: Direct OCSP requests allow Certificate Authorities to see which clients are visiting a particular site. By using OCSP stapling, this information is no longer shared, which protects user privacy.
- Reduced Load on Certificate Authorities (CAs): It minimizes the volume of requests that CAs must handle, improving reliability and responsiveness of the CA systems.
These advantages make it a powerful tool for enhancing SSL connections, making it an increasingly popular choice for website owners and administrators.
Difference Between OCSP and OCSP Stapling
Understanding the distinction between traditional OCSP and OCSP stapling is essential for grasping why it is preferred for modern SSL implementations.
In a traditional OCSP setup, the client directly queries the CA to verify the certificate status. While effective, this process can lead to slower loading times, as each query introduces a new external request. Moreover, traditional OCSP exposes the client’s IP address to the CA, which can raise privacy concerns.
With OCSP stapling, however, the server handles this OCSP response request on behalf of the client. It retrieves and caches the digital certificate’s status directly from the CA, allowing it to “staple” this response to the SSL handshake. This way, the client gets the certificate verification without the additional request, resulting in faster and more private SSL verification.
Alternatives to OCSP Stapling: OCSP Must-Staple
For websites needing an extra layer of SSL security, OCSP Must-Staple is a compelling alternative. This feature requires the server to always include a valid OCSP response during the SSL handshake. OCSP Must-Staple adds a security directive to the SSL certificate itself, instructing browsers to reject the certificate if a stapled OCSP response isn’t provided by the server.
Key Benefits of OCSP Must-Staple
- Ensures Fresh Certificate Validation: Unlike standard OCSP stapling, which may provide an outdated OCSP response, OCSP Must-Staple demands that the response is both valid and recent. This ensures higher levels of trust in the certificate’s status.
- Increases Security Standards: By enforcing OCSP stapling as mandatory, OCSP Must-Staple reduces the risk of an invalid certificate going undetected by clients, making it ideal for sites prioritizing high-security standards.
While OCSP Must-Staple offers enhanced security, it may not be suitable for all sites. For instance, smaller websites or sites without high-security needs might find the standard OCSP stapling setup sufficient.

Cons of OCSP Stapling
While OCSP stapling offers notable benefits, it’s also essential to consider potential drawbacks and limitations.
- Server Dependency: Since the OCSP response is provided by the server, the server is responsible for regularly updating and caching valid responses. If the OCSP response becomes outdated or invalid, it could affect SSL handshakes.
- Compatibility Issues: Some older clients may not fully support OCSP stapling, leading to potential compatibility issues. However, most modern browsers and devices can handle stapled OCSP responses.
- Single Point of Failure: If the OCSP stapling mechanism encounters issues, it could prevent clients from confirming the SSL certificate status, potentially interrupting user access.
How to Enable OCSP Stapling?
Below, we’ve provided instructions for enabling OCSP stapling on the ever-popular Windows, Apache, and Nginx servers.
Enable OCSP Stapling on Windows
OCSP stapling is enabled by default on Windows Server 2008 and later versions. If you’re running an earlier Windows Server release, enabling it is not possible. Please, update to Windows 2008 or later.
Enable OCSP Stapling on Apache
Apache supports OCSP stapling starting from Apache HTTPD Web Server 2.3.3+. If you don’t know which version you’re running, use the following commands:
apache2 –v
httpd –v
Next, check if OCSP is enabled. Follow the steps below:
- In OpenSSL, enter the following command:
openssl.exe s_client -connect [yourdomain.com]:443 –status
If OCSP is enabled, you’ll receive the following response in the OCSP Response Data section: “OCSP Response Status: successful (0x0)”. If OCSP is not enabled, you will not see any OCSP response data. In this case, make sure your intermediate certificate is installed correctly. - Verify if your Apache server has successfully connected to the OCSP server. Run the command below:
curl ocsp.digicert.com/ping.html - To enable OCSP stapling, you need to edit the virtual host configuration file for your site (your-domain.com-ssl.conf) using the editor of your choice. The configuration file usually resides in the following directory: etc/apache2/sites-available/your-domain.com-ssl.conf
- Open the file and make the following changes:
- Add the following lines inside the <VirtualHost> tags:
SSLUseStapling on
SSLStaplingResponderTimeout 5
SSLStaplingReturnResponderErrors off - Add a line inside the tags which points to a trusted certificate chain file. This must contain the intermediate & root certificates in order:
SSLCACertificateFile /etc/apache2/ssl/full_chain.pem - Add the following line outside the <VirtualHost> tags:
SSLStaplingCache shmcb:/var/run/ocsp(128000)
- Add the following lines inside the <VirtualHost> tags:
- Test your configuration:
apachectl –t - Restart the Apache server
apachectl restart
Enable OCSP Stapling on NGINX
It is available on NGINX 13,7 or later. Check your NGINX web server version:
nginx-v
Use the following OpenSSL command lines:
- Check if it is enabled. In OpenSSL, run the following command:
openssl s_client -connect [yourdomain.com]:443 –status - If OCSP is enabled, the OCSP Response Data section should say: OCSP Response Status: successful (0x0)
- If it is not enabled, you won’t see any OCSP Response Data. If you don’t receive confirmation that OCSP is enabled, use this troubleshooting guide.
- To enable it, first, edit the server block configuration file for your site (or nginx.conf if server blocks are not used):
nano /etc/nginx/sites-enabled/my-domain.com-ssl.conf
or
nano /etc/nginx/nginx.conf
Note: If you need to enable it on just one server block, it must be the “default_server”. If you need to enable it on several server blocks, it must be enabled on the ‘default_server’ first. Then it can be enabled on any other server block. - Turn on OCSP stapling and enable the server to check OCSP stapling by adding two lines inside the server block:
ssl_stapling on;
ssl_stapling_verify on; - Indicate a trusted certificate chain file which contains the intermediate & root certificates in order:
ssl_trusted_certificate /etc/nginx/ssl/full_chain.pem - Check your configuration:
sudo service nginx configtest - Restart NGINX:
sudo service nginx reload
Bottom Line
At SSL Dragon, we’re dedicated to helping you navigate the complexities of SSL/TLS security to provide the best possible browsing experience for your users. OCSP Stapling is a powerful tool for boosting both speed and privacy in SSL connections, making it an essential feature for modern websites.
We offer a wide selection of SSL certificates that support OCSP Stapling, ensuring that your site meets the highest standards of speed and security. Start optimizing your SSL setup today and see the difference in faster, more secure connections.
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