I was asked this by a school district using a hardware load balancer. I found a useful internal reference:
Note: you can also lock down the MAPI RPC TCP high ports to two specific RPC high ports if needed (one for public folders and one for mailbox connections). Good description on how to set this here.
<p>You also would need to force the DOMT port if your load balancer can't do ranges (many can't).</p>
<p>You can use the same port for PF and MOMT since they're running on different servers.</p>
<p>Also that note column is wrong. Unicast works with a broader set of switches but it /WILL/ flood the vlan. Multicast will /not/ flood the vlan. </p>
<p>With 2008 R2 you can do single NIC unicast. </p>