ESXI-06-000004 - Remote logging for ESXi hosts must be configured.
Remote logging to a central log host provides a secure, centralized store for ESXi logs. By gathering host log files onto a central host it can more easily monitor all hosts with a single tool. It can also do aggregate analysis and searching to look for such things as coordinated attacks on multiple hosts. Logging to a secure, centralized log server also helps prevent log tampering and also provides a long-term audit record.
From the vSphere Client select the ESXi Host and go to Configuration >> Advanced Settings. Select the Syslog.global.logHost value and configure it to a site specific syslog server. or From a PowerCLI command prompt while connected to the ESXi host run the following commands: Get-VMHost | Get-AdvancedSetting -Name Syslog.global.logHost | Set-AdvancedSetting -Value '<insert syslog server hostname>'