When looking for which ports Exchange 2010 uses, you probably already read the excellent Exchange 2010 Network Port Reference TechNet article located here.
However, at some point, like when discussing things with the network/firewall people or documenting your design, it might be required to visualize things. For this purpose I created the following diagram:

Note that it’s a v1 and not all things are included, e.g.

  • Internal clients, e.g. Outlook, OWA;
  • UM connections to PBX;
  • Client Access Server connections to OCS;
  • For Hub-Hub, CAS-CAS or Edge-Edge, I’ve included a 2nd Hub/CAS/Edge server only mentioning ports used for Hub-Hub, CAS-CAS and Edge-Edge communications.

Also, all ports are left at their default values and the diagram doesn’t reflect the fact that you can fix certain ports like the one for the DAG or the MAPI RPC port; that might be added in a later version.
When you got feedback, fill in a comment. Otherwise, feel free the use it; crediting or a reference would be nice.

Source: eightwone.com/2010/12/27/exchange-2010-network-ports