ICSMGR gets installed on any PC which shares an Internet connection using Microsoft's Internet Connection Sharing protocol (ICS). This program, which relays all DNS and DHCP requests, is vital if your PC is accessing the Internet via ICS.
Recommendation :
Leave alone if you are on an ICS network. If you are not, remove Internet Connection Sharing (ICS) from the Network icon in your Control Panel as its presence can often cause [sometimes serious] conflicts or unnecessary complications when you are configuring network components of your PC.