What is the Microsoft Loopback adapter? - KB Article - 162381

The Microsoft loop back adapter is a software simulation of an adapter.

The Microsoft loop back adapter is a software simulation of an adapter that Dell installs on all laptop computers running Windows NT.  It is installed so that when the Operating System is updated with a service pack (currently Service Pack 4), the networking components will also be updated.

This component will not affect your networking.  However, usually when TCP/IP protocol is added to the system, the loopback adapter will have DHCP enabled as its source of IP addresses.  This causes the system to boot up slowly, and at least one DHCP failure error.  For this reason, Dell strongly recommends the removal of the Microsoft Loopback adapter after installing the system''s own Network Interface Card.