OCSP Stapling optimization in Nginx reverse proxy

Nginx is a widely used high-performance web server and reverse proxy server. The reverse proxy server provides specific network services to clients through proxies. It plays a vital role in the field of network security. In the reverse proxy process, handling SSL certificate verification is a very important step. OCSP Stapling is a mechanism that optimizes the SSL protocol and can provide faster and more secure SSL certificate verification. This article will focus on the OCSP Stapling optimization method in Nginx reverse proxy.

1. Overview of OCSP Stapling

Before focusing on the OCSP Stapling optimization method in Nginx reverse proxy, let’s first understand what OCSP Stapling is.

OCSP (Online Certificate Status Protocol) protocol is a protocol used for certificate status checking, which can check the revocation status of SSL certificates. During the TLS handshake process, the client requests the server for SSL certificate verification, and the OCSP protocol is used to provide verification services. However, since OCSP access requires a request to the certificate authority CA, this process may cause network delays and security issues.

OCSP Stapling transfers the process of checking the SSL certificate revocation status to the Web server side instead of the client side. The OCSP response of the SSL certificate is periodically obtained from the CA through the Web server (such as Nginx) and stored in memory. Then during the process of establishing an SSL connection with the client, the web server will return the cached OCSP response to the client. This method can not only increase the speed of SSL connections, but also avoid the security issues of clients making requests to the CA.

2. Enable OCSP Stapling in Nginx

The method to enable OCSP Stapling in Nginx is very simple. You only need to add the following code to the SSL certificate configuration:

ssl_stapling on;
ssl_stapling_verify on;
ssl_trusted_certificate /path/to/ca-certs;

Explained here Here’s the meaning of each option:

• ssl_stapling on: Enable OCSP Stapling mechanism
• ssl_stapling_verify on: Verify whether the OCSP response is trusted
• ssl_trusted_certificate: Provide a CA certificate chain , used to verify OCSP response

After Nginx enables OCSP Stapling, it will automatically initiate an OCSP request to the issuing authority of each SSL certificate and cache the OCSP response into memory, with a validity period of 10 minutes. If the validity period of the OCSP response exceeds the cache time, the OCSP response will be re-requested from the issuing authority. When the client establishing an SSL connection requests verification, the web server (such as Nginx) will return the cached OCSP response to the client. This process will not affect the speed and security of the SSL connection, and can also effectively prevent malicious attacks.

3. OCSP Stapling optimization

In addition to enabling OCSP Stapling in Nginx, we can also perform some operations to further optimize its performance and security.

1. Caching OCSP responses

Nginx caches OCSP responses into memory by default, but when the server restarts or the cache fills up, OCSP Stapling will re-request the OCSP response from the CA , which requires time and network bandwidth. To avoid this situation, we can cache the OCSP response to disk so that even if the server is restarted, the OCSP response will not be lost. We only need to add the following code to the Nginx configuration file:

ssl_stapling_file /path/to/ocsp_response.der;

Among them, /path/to/ocsp_response.der is the path and file name of the OCSP response cache.

2. Using multiple CA certificates

If we use multiple CA certificates to issue SSL certificates, then each issuing authority will have a different OCSP response. In this case, we can cache multiple OCSP responses simultaneously. We only need to add the paths of multiple OCSP response files to the ssl_trusted_certificate directive, for example:

ssl_trusted_certificate /path/to/ca-certs1 /path/to/ca-certs2;

3. Update the OCSP response more frequently

The validity period of the OCSP response is 30 days, but we can update OCSP responses more frequently to improve security. We only need to set the cache time of the OCSP response shorter, for example:

ssl_stapling_responder_timeout 5s;
ssl_stapling_verify_result on;

Among them, ssl_stapling_responder_timeout is used to set the cache time of the OCSP response, here it is set to 5 seconds, and ssl_stapling_verify_result is used to verify the result of the OCSP response.

4. Update OCSP responses regularly

Even if we set the OCSP response cache to be very short, there is no guarantee that it will always be up to date. So we also need to regularly update the OCSP response, which can be achieved through Nginx's scheduled tasks, for example:

0 * * * * /usr/sbin/nginx -s reload

This task will reload the Nginx configuration file at the beginning of each hour and re-enable OCSP Stapling mechanism.

4. Summary

The OCSP Stapling mechanism in Nginx reverse proxy can improve the speed and security of SSL connections, while also preventing malicious attacks. The performance and security of OCSP Stapling can be further optimized by caching OCSP responses, using multiple CA certificates, updating OCSP responses more frequently and updating OCSP responses regularly. Therefore, when using Nginx reverse proxy server, we should enable OCSP Stapling and perform necessary optimizations.

The above is the detailed content of OCSP Stapling optimization in Nginx reverse proxy. For more information, please follow other related articles on the PHP Chinese website!