telnet is disabled and verbotten in our environment we only allow SSH so I'd like to turn the protocol off altogether. Having it active generaes error messahges in the logs and annoying popups everytime I run any discovery "by shell"
You can leave the telnet credentials empty (don't provide any) and at least UD won't be trying any. If you really want to stop it, there's probaby a way. Make a copy of the particular discovery package by exporting from the package manager. Modify the copy, removing triggers and calls to telnet, import under a new name, and create a new discovery job using the new adapter. Use naming conventions that make it clear it's your custom adapter and job.