Today I installed a new vCenter 5.5 server in a environment without a domain and DNS server. During the deployment of vCenter Single Sign On I received this error message:
Error 29101 Could not connect to vCenter Single Sign On. Make sure that the Lookup Service URL points correctly to the vCenter Single Sign On instance you installed. If vCenter Sign On is installed with an IP address, make sure the IP address is specified in the URL.
Select: “Use FQDN instead of IP address to configure vCenter Single Sign-On”