I have configured our managed servers (on WebLogic 10.3.5) to use SSL with custom identity/trust keystores and all that has been working fine. However, after completing the SSL configuration, we started getting some warning messages saying "Invalid/unknown SSL header was received from peer". After looking through some articles online, the solution seemed to be setting the SecureListener property in nodemanager.properties to "false" and setting the listener type of the Node Manager in the Administration Console to "Plain". This did stop the warning messages from showing up in the log file...however I was wondering if there are any security implications to using a plain vs. SSL listener for the Node Manager. FYI, this is a development environment that's closed off from public access but will eventually be moved to a production environment.