IT is running port scans regularly on all network attached machines campus wide to identify any potential security concerns. If your Mac computer is scanned, your Symantec Endpoint Protection software may show a "Vulnerability BLOCKED" message. If you click "Options->More Info" and the IP address is from either 129.186.6.24, 129.186.6.25, or 129.186.6.4, you can simply ignore this message. See below for an example.