I was performing a NMAP port scan against a test ESXi 4.0 box so we can document what ports it is listening on. All the standard ports came up (80, 427, 902, etc.) but NMAP also said 123 UDP, 8301 and 8302 UDP were open/filtered. I know UDP 123 is NTP time, but I would have though ESXi initiated the communications with the NTP server and wouldn't be listening all the time on 123?
I also tried to Google UDP 8301 and 8302, and came up with no hits related to ESX. Is this just a NMAP glitch, or is ESXi 4.0 really listening on these UDP ports? If so, why?