"Cannot connect to vCenter Single Sign On" / Lookup Service errors when installing Web Client 5.5 on a Windows machine in a workgroup
If you're like me and don't want to spend extra time adding Microsoft components and products to your vSphere lab, you might forgo the domain controller and simply use a workgroup machine with the DNS role as your vCenter host.
When evaluating vCenter 5.5 in a lab without a Windows domain controller, you'll need to configure the primary DNS suffix of the host machine under system properties. Appending the suffix under the network adapter configuration does not suffice.
Ensure that DNS includes your forward & reverse zones, and that all vCenter infrastructure hosts have records resolving in those zones.
You'll see the FQDN listed as "hostname.xxxx.xxx" in the SSO installer, vs just the hostname.
After I ensured the SSO installer recognized the complete FQDN of the host, my Web Client installation proceeded without error. When prompted for FQDN in other vCenter installers (Inventory Service, vCenter Server,) always use the FQDN and don't let it pass just the hostname through the installer. You should be good to go!
