In the current version it is not possible to turn off the http server. In newer versions it will be possible to turn it off. However keep in mind that Vmware Update Manager conencts to the VSM using http to get the VEM code. If you block or turn off http on the VSM it will prevent VUM from working and you will have to install all the VEM modules manually on the ESX hosts.
Also by default the VSM and vCenter communicate via port 80. It is possible to change this to another port but just realize that the VSM connects to port 80 on vCenter to communicate.
So if you block incoming port 80 to VSM then VUM will break
If you block outgoing port 80 from VSM then connectivity to vCenter will break
louis
