Digital certificates are at the heart of the TLS secure communication on all the platforms. Applications running on z/OS can be a server communicating with a client application running on Windows or Linux or vice versa. RACF keyrings are used in the typical set up in the TLS protocol. There is a lot of confusion on what certificate(s), what authority needed. This session will cover the basic set up on keyring and certificates and the steps to figure out the problem.