Ron, you really need to provide more information:
- where did you see this notice, on a workstation?
- what were you doing at the time?
- How often does this notice comes up?
- Please describe how your SME server is configured (gateway?).
- How is the server connected to the Internet (router?) Any other devices between the server and the Internet?
- How is your server connected to the local network (switch or switches?). Any other devices?
Also check /var/log/messages (or in server-manager, under view log files) and see if there is anything unusual at the time of the notice.