High SSL Connection Time

Why am I seeing this diagnostic?

As a webapp developer, you're likely familiar with SSL (Secure Sockets Layer) or its successor, TLS (Transport Layer Security). SSL/TLS provides secure communication over the internet by encrypting the data exchanged between your webapp and the API server. When your webapp establishes an SSL connection with an API server, several steps are involved. The key stages are SSL Handshake, Certificate Validation and Key Exchange followed by the subsequent secure communication.

High SSL connection times indicate that the time taken to complete the SSL handshake and establish a secure connection is longer than expected. This can be caused by factors such as inadequate server resources to handle SSL handshakes, slow or congested network connections, misconfigured SSL/TLS settings, latency introduced by certificate validation, or outdated SSL/TLS protocols and cipher suites being used.

This can have several implications for your webapp:

1. Increased latency: Lengthy SSL connection times directly contribute to the overall latency of your API connections. It delays the start of data transmission, impacting the response times from the API server.

2. Performance impact: If your webapp relies on multiple API connections, each with its own SSL handshake process, the cumulative delay can significantly impact the overall performance and responsiveness of your application.

3. User experience: Slow SSL connection times can lead to user frustration, as they perceive the webapp as slow or unresponsive. It's crucial to provide a smooth user experience, especially during initial connection establishment.

How do I fix this?

To optimize SSL connection times and mitigate these issues, consider the following:

1. Certificate management: Certificate validation can be a resource-intensive process, so ensure that the SSL certificates used by the API server are valid, not expired, and issued by trusted CAs. Caching validated certificates can also help reduce SSL connection times.

2. Cipher suite selection: Review the cipher suites supported by your webapp and the API server. Choose cipher suites that strike a balance between security and performance.

3. Keep-alive connections: Consider implementing keep-alive connections, which allow multiple requests to be sent over the same SSL session. This reduces the number of SSL handshakes required for subsequent requests, improving overall performance.

4. Network optimization: Evaluate your network infrastructure, including server location, bandwidth, and network congestion. Network-related factors can contribute to SSL connection delays, so optimizing network configurations can help improve SSL connection times.