XenServer Administrator's Guide
Troubleshooting
204
Also, if you upgraded your software from version 3.2.0 to the current version, you should also have received and applied a new License file. For details on licensing a host, see the chapter "XenServer Licensing" in the XenServer Installation Guide . • The XenServer host talks to XenCenter using HTTPS over port 443 (a two-way connection for commands and responses using the XenAPI), and 5900 for graphical VNC connections with paravirtual Linux VMs. If you have a firewall enabled between the XenServer host and the machine running the client software, make sure that it allows traffic from these ports.