The following ports have special use in the GN4 system and must not be used by any other 3rd party software, otherwise your GN4 system or its parts may stop to function.

•Port 80. Although it is not common (and neither recommended) that you install Skype on a GN4 server, have in mind that Skype takes over port 80 and it may prevent IIS to start correctly. In such case, uninstall Skype, or - if that is not possible - exit Skype before restarting IIS. Have in mind that the Skype service, permanently running on an IIS server, may prevent all the maintenance or upgrading operations that require stops and restarts of IIS service.

•Ports in a range 7373 - 7372 + number of Back4 servers. For example, if you use only one Back4 server, it will be using the port 7373 by default. If you install another Back4 server, it should be using the port 7374, and so on. Have in mind that the port number may be changed in GN4, but in no case, the ports used by Back 4 should not be given to other software.

•Ports in a range 10000 - 10100. Those ports are used by Exalead search engine. If Exalead is installed on your GN4 system, then those ports must not be used by any other software.

In case of problems, see Troubleshooting 'port in use' problems.