I would like for my 4507 to be the ntp server for my LAN. It looks like I have to configure the NTP broadcast on a specific interface. So how does that work for the rest of the network or do I have to configure it on every single one of my interfaces?
My 4507 is already synched with external ntp sources.
Great, then you should be all set.
I just want our servers domain controllers and the like to use the core as the ntp server. So configuring the core as an ntp master is the key?
Yes, but there can be compatability issues between Windows and Cisco, you may need to just test and see what happens. At my last place we had a dedicated time server that we peered a Cisco router to and then peered all our Cisco devices to that router and the Windows guys peered directly with the dedicated time server.
Also are you intending to sync the master 4500 with an internet time server or are you more concerned with just syncing devices to the same time with your LAN ?