When you set up SharePoint 2010 you given the option of accepting the randomly assigned central admin port or selecting your own. Now because I like to know where my central administration site I usually pick my port number and to make like easy I take something easy to remember like port 10000. Normally this is not an issue as nothing is normally running on a port that high.
Recently I came across an issue whereby after a system reboot to update SharePoint with the latest ADO.NET Services software, the central administration site would not start and IIS would not bind to the port as it said it was already in use. It was a bit strange and I couldn’t figure out what had changed to the system other than my update.
Using the command line tool netstat I eventually found the culprit. BackupExec had been deployed to the domain and that uses port 10000 as a control port. Once this was figured out it was a simple case of changing the central administration port to another port and you can do this with PowerShell using the Set-SPCentralAdminstration –Port <PortNumber> (details)
So mind your ports!