For 11.3 and above: The platform for the ESA Device has changed with the release of the Correlation Server as opposed to the traditional rsa-esa and rsa-nw-esa-server. The esa-client will no longer work in 11.3 and above. You have two ways to find this information. The easy way is to go to Health and wellness and look for the sessions behind value in the UI like below. Note you will have one for each deployment and each device being aggregated from.