It is probably workaround #2 the esxcfg-firewall
Try these helpful workarounds
Update Manager fails to scan an ESX Server for updates when using non-default Web Services HTTP port
This error occurs if the web service HTTP port in VirtualCenter is not set to the default port (the default port is 80).
Perform one of the following workarounds based on your situation.
Workaround 1
VMware Update Manager automatically opens firewall ports 9000-9100 on ESX Server 3.5 during scan or remediation. If port 80 cannot be used as the web service HTTP port, use a port in the range of 9000-9100:
Log in to the Virtual Infrastructure Client and click Administration.
Click VirtualCenter Server Management Server Configuration.
Click Web Service.
Change the HTTP port to a new value, within the 9000-9100 range.
Click OK and restart VirtualCenter Server service.
Restart the Update Manager service.
Log in to Virtual Infrastructure Client after both VirtualCenter and Update Manager services have been restarted,
Disable the Update Manager Plug-in in the Virtual Infrastructure Client and re-enable it.
Workaround 2
If port range 9000-9100 cannot be used as web service HTTP port in VirtualCenter:
Enable the custom VirtualCenter web service HTTP ports in the ESX Server's firewall by entering the following command in the service console:
esxcfg-firewall --openport ####,tcp,out,dynamicupdates
Note: #### is the custom port being used by VirtualCenter.
You can check the custom port by logging into VirtualCenter and clicking Administration Menu > VirtualCenter Management Server Configuration > Web Service.
Restart the Update Manager service.
Log off and log in to VirtualCenter using the Virtual Infrastructure Client.
Disable and re-enable the Update Manager plug-in.
If the problem still exsists try reading through the attached document.
Message was edited by: dmn0211
