vSphere hosts disconnecting

I recently reinstalled by entire vSphere & Veeam infrastructure (old install was not playing nice with a large SQL database - too many big jobs running overnight at the same time). Overall it all went really smoothly - point the new vSphere at the ESXi hosts and it warns that the old vSphere will be disconnected, Veeam installed and connected with no problems (or so I thought). Unfortunately I tested a Veeam backup before I enabled the Windows Firewall which lead to everything failing on the first night. Windows firewall needs a few ports opened for vSphere to remain connected to the ESXi hosts. After a few minutes all the hosts show as (not responding) in the vSphere client.

A full list of the ports for VMWare products can be found here http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1012382

However if you are just wanting to connect your vSphere server to your ESXi hosts then these are the ports that need to be open on the vSphere server (assuming you have installed on Windows and not used the new vSphere appliance)

For vSphere/ESXi 4.x you need the following:

TCP port 111 NFS Client - RPC Portmapper (NFS needed for Veeam's instant recovery feature)
TCP port 2049 NFS Client
TCP and UDP port 902 Heartbeat (This is the important one!)

vSphere/ESXi 5.x also needs these (but I have not tested as still on 4.x until Veeam adds full support)

TCP port 5989 CIM XML transactions
UDP port 111 NFS Client - RPC Portmapper (NFS needed for Veeam's instant recovery feature)
UDP port 2049 NFS Client

As soon as you enable the two heartbeat protocols your hosts should automatically reconnect and then everything should work. Lesson learned - wait for timeouts after enabling firewall before assuming its all working!