Session Resumption Checker

Check if TLS session resumption is supported

About Session Resumption

TLS session resumption allows clients and servers to reuse previously negotiated cryptographic parameters, significantly reducing the latency of subsequent TLS handshakes. There are two main mechanisms: session IDs (server-side cache) and session tickets (client-side encrypted tickets). Our tool tests both methods and reports whether your server supports them, along with performance measurements.

How to Use

Enter the domain name of the server you want to test.
Click "Check" to run the session resumption analysis.
Review the results showing session ID support, session ticket support, and handshake timing data.
Use the findings to optimize your TLS configuration for better performance.

Use Cases

•Verify that session resumption is properly configured on production servers
•Measure the performance benefit of enabling session tickets in high-traffic environments
•Troubleshoot slow TLS handshakes caused by missing session cache support
•Ensure load-balanced servers use consistent session cache configurations

Frequently Asked Questions

TLS session resumption lets a client and server reuse previously established cryptographic parameters, skipping the expensive public-key operations in a full TLS handshake. This reduces latency from two round trips to just one (or zero with 0-RTT).

Session IDs are stored on the server side, requiring the server to maintain a cache. Session tickets (RFC 5077) are encrypted and stored on the client, eliminating the server-side cache requirement and making them ideal for load-balanced environments.

Without session resumption, every new connection requires a full TLS handshake involving CPU-intensive asymmetric cryptography. With resumption, subsequent connections can be established in as little as one round trip, reducing page load times and server CPU usage significantly for sites with many returning visitors.

Tips & Best Practices

•Enable session resumption to improve TLS handshake performance
•Monitor session resumption rates for performance optimization
•Configure appropriate session cache size for your traffic volume
•Balance session resumption benefits with security requirements

Technical Details

Mechanism: TLS session resumption (session IDs and session tickets)
Performance: Handshake time reduction through session reuse
Cache: Session cache configuration and management
Output: Session resumption status with performance analysis