I've got an older Cisco 2821 running IOS 15.1 IIRC, and for some reason, whenever I try to specify an NTP server, I get this: Code: ROUTER(config)#ntp server time-a.nist.gov Translating ...
IIRC windows doesn't run ntp by default, it runs some propretary w32time service instead. I think it has an ntp client built in, but I'm not sure if it can be an NTP server out of the box.