Fedora :: Use NTP To Set The Time Automatically?

I am going nuts because this should a simple thing and for some reason it's not. 1. I'm just trying to use NTP to set the time automatically. I've done numerous installs and had it work fine. However for my Fedora 11 box and this Fedora 13 box, it's not working. I'm getting a vague error "unable to connect to server." Which could mean anything. As near as I can tell, it should be simple:

a. Select to use NTP.
b. Adjust the local firewall to allow connections at 123 (ntp)
c. If necessary, adjust the router settings for port 123.

I have tried sending port 123 traffic directly to my Fedora 13 machine, but same error. I've tried using other choices of ntp server (like the North America pool). No dice. I've had two separate routers, first a Dlink and now a Cisco. Same problem. I've checked the SELinux logs for errors but didn't notice anything obvious (that doesn't mean much -- I'm not much of an SELinux guru). I've set up Fedora 14 at work and it connected just fine. Didn't have to open anything other than the local port on the Fedora firewall. No network/router adjustments needed.

It's not a giant thing but it's driving me nuts. Anyone out there have any suggestions? Particularly big obvious things that maybe I've overlooked? Does some other setting override this NTP time? Does using this require use of GMT? Something like that?