If your Internet access is restricted, you can set up your own internal repository for updates, instead of updating from a VMware public repository. You can download updates as a zipped update bundle from the Product Download page.
To patch the vCenter Server Appliance from a VMware public repository, see Configure the Repository for URL-Based Patching. To patch the vCenter Server Appliance from the virtual CD-ROM drive of the appliance, see Install vCenter Server Appliance Patches. For major upgrades to the vCenter Server Appliance, see Upgrading the VMware vCenter Server Appliance.