vSpeher 5 Web Client seems to have a bug in in vmrc.jsp called due to "Launch Console" action.
Setup:
vCenter Essesntial server installed at custom port of 9433. It has two hosts in its datacenter. All VMs console are accessible using vSphere Client on Windows. vCenter Web Client is installed at custom port of 7433. Correctly registered vCenter server (as gemini:9433) with it using admin-app. Able to connect to https://gemini:7433/vsphere-client/ and view all VMs and other details.
Problem:
In vSpeher Web Client, when pressing "Launch Console" action for any VM, the pop opens with VMRC and tries to connect for long time and then times out with message suggesting no connection with host. However, the VMRC can connect to VM if invoked from command line vmware-vmrc.exe -h gemini:9443 -M <id>.
Investigation:
The web page generated source, shows a line vmrc.Connect ("gemini",.........) in vmrc.jsp. I think it should be gemini:9443 as given during registration and not just host name. I modifed the vmrc.jsp on server to concatenate ":9443" along with hostname and after this fix, "Launch Console" action correctly starts VMRC and makes successful connection.
The bug in vmrc.jsp is due to fact that instead of complete server address given in registration, it uses just hostname assuming the default port. This problem will not come on setups where vCenter Server is installed at deafult port of 443. The problem is only there if vCenter is running on custom port.
My Workaround:
Locate extracted vmrc.jsp on server side. Change vmrc.connect call to pass port along with hostname.