qestion for option-advanced

[Fannie]

Any one knows "query ocsp responder servers to confirm the current validity of certificate" means what? does it necessary to choose or not?
like below "tools-options-advanced-certificates" :

[tanstaafl]

https://en.wikipedia.org/wiki/Online_Ce ... s_Protocol

It uses the OSCP protocol to determine if the certificate used in a secure connection is still valid. i.e. it helps verify that you are really connecting to the mail server that you think you are using. I leave it checked as it doesn't add a noticeable delay and I have never had a problem due to it. You might have different results.

[Fannie]

thinks very much, it's very usefull for me.