When a process opens a listner on a specific name:port then that is 'locked' by th eoperating system so that no other process can open the same listner.
Issues relating to listners can manifest themselves in one of 2 ways depending on who starts the listner first:
- If the AppGate client is first then issues such as a user no longer being able to download packages from SCCM using Background Intelligence Transfer System(BITS) and Branch cache. This is because the AppGate client may well be using localhost:80 already.
- The alternative is when the AppGate Client reports an error message, "..could not start listener on local address 127.0.0.6:XX ..", which is typical when there is an other application using this port already; which maybe something such as Skype. So thid error oes not indicate a problem with the hosts file/iptd; but if the client fails to open the listener it is no point for it to write to the hosts file.
To check if there is an application keeping port XX in LISTENING mode. Use one of the commands below to find out. Once you identified the application who owns the port, close it and try again connecting with the appgate client.
Windows 7, 8, run as admin
sudo lsof -i -P
sudo netstat -tulpn