X terminals are special-purpose computers with a display, one or more input devices, and some kind of communications interface. The X terminal runs a copy of the X server, and usually all X clients are running on other hosts. Most X terminals have thin, thick, or twisted-pair ethernet communications interfaces, and support TCP/IP. Several vendors sell X terminals with serial interfaces and an X server which understands their proprietary serial version of the X protocol. Others sell X terminals which use Digital Equipment Corporations LAT protocol. X terminals are attractive because they are less expensive than workstations and they require less management.
Some insecurities which are somewhat peculiar to X terminals (although
diskless X workstations may also be vulnerable):