Here's an overview of the online check tools I have used to check my webserver configuration. In the last days I was curious about optimizing the caching behavior and the related HTTP headers sent from my webserver. And I also checked the SSL configuration and content readability.
SSL Configuration
The checker from SSL Labs provides a very detailed analysis of the SSL configuration, including supported SSL / TLS protocol versions, supported ciphers and protocol negotiation results for various browsers and versions.
Based on the results I have now disabled old TLS protocol versions 1.0 and 1.1 on my Apache webserver and now get an A+ rating from them.
You can see the report for this server here: SSL Labs Test Report
Caching and Website Speed
The speed check on pingdom provides a an overview about how fast a web page is loading and checks for general topics like expiration headers. Based on the results from these pages I have added the HTTP Expires Header.
redbot has a focus on the HTTP headers.
Readability
I think speed is not only about the technical speed of the web server and browser. I think it also matters if visitors can easily read my content. So I also ran a test for readability: WebFX Readability Test
Here's an example result: WebFX Report