I am having issues with 3600 and 7200 routers not sysncing with NTP server. My NTP server is working fine as I have other devices syncing to it. The 3600 and 7200 routers can sync to public NTP servers on the internet but cannot sync to my internal NTP server. The routers do have access to the NTP server because they and ping and traceroute to it.
If you can ping the NTP server address sourcing the ping from FastEther2/0 then that does demonstrate IP connectivity, which is one of the first things I would look at. So that is good.
Based on the information so far I am suspicious about the firewall(s) and whether they are blocking some NTP traffic. I had a situation at a customer site once where their firewall was permitting only if both source port and destination port were NTP. There was a device sending NTP requests but the source port was some high port - and was being blocked even though it was a very legitimate NTP request. Could something like that be going on that does permit NTP from some devices but not from others?