MacTCP

MacTCP DNR is described as a control panel by the Finder, yet it is notably absent from the Control Panels folder -- only to be found loose in the root level of the System Folder. And it cannot be opened!

This unopenable control panel is nonetheless essential. As it is a "domain name resolver" (DNR) for MacTCP, it is needed by certain Internet, i.e. TCP/IP applications.

This control panel is only really needed if you are surfing around the Web without Open Transport-compatible applications and you are using an Internet account excluding America Online. If you access the Web this way, any attempt at removing this control panel will result in it being recreated, in itself, the next time you sign on!