WordPress as Intranet on Internal Network (No Internet Access)

Hi there, we have installed WordPress on our internal network (no internet access) with the sole purpose as using it as our Intranet.

I notice that WordPress does try to talk to the outside world (e.g. gravatar.com) and wonder if there is any support documentation as to what connections WP is trying to make and how to remove them for this scenario.

Any help much appreciated.