The port range 17871 to 17890 must be open because iManage Work Desktop for Windows communicates internally at 127.0.0.1 on port 17871 and 17872, if 17871 is busy. It will try the next available higher port if 17872 is also busy. If you are using a third-party firewall, it may block the iManage Work Agent system tray application unless you have a policy set up to allow access. This will interfere with some actions available in iManage Work web application. You can test if the port is busy by pinging the port. For example, http://127.0.0.1:17871/ping.
If iManage Work Desktop for Windows is installed in multi-user environments such as Citrix, iManage Work Agent Service listens on 17871 and individual iManage Work Agent instances running under each signed in user's account listen on the range of ports immediately above 17871 (17871 to … ).