Need Dns And Other Services_server App


I inherited a Mac OS X 10.8 server that is now only used as a file server. I'd like to confirm some things.
Within the Server Apps settings it has File Sharing, Contacts, DNS, Mail, and Software Update services on. We have enterprise DNS servers which I configured in the general network adapter settings.

Is there any reason (I can't think of) where I'd need to continue to have DNS service "on" if I can rely on enterprise DNS servers to supply DNS routing for this server? Also, do I need to keep running the Mail service for any advisable reason (e.g. maybe so it can send server notifications, etc)? And would this be the only reason to run the Contacts service?