Blocking OS and Firmware Updates (Firewall)

Hi
First post here. My company uses 3rd party full-disk encryption software which can conflict with firmware updates from Apple. We are looking for a way to prevent our users from updating the firmware on their MacBooks (they had admin rights) until we have had a chance to test compatibility.

I know there are management solutions like the Casper suite which allow you to block updates through policy, but even then you have to know the update name/number and then push a policy and naturally Apple doesn't release this information ahead of time.

What we were thinking was creating a desktop firewall rule that prevents connecting to the update servers... anybody know if this would work and what the server names/IPs to Apple updates servers might be?

Thanks

 

Thanks- but even with a Lion Update Server, the user can still install updates on their own can they not?