Telnet and FTP refer to basic network utilities (and related protocols) that allows a user to interact with a remote host using a text-based virtual terminal. Telnet and FTP are both widespread (they are integrated into many operating systems) and useful. You may have telnetted from your home Windows PC to a UMBC Unix server to check your email with Pine, or transferred files between 2 computers using FTP.
Unfortunately, telnet and FTP are inherently insecure. When you initiate a telnet or FTP connection, your username, password and other bits of important information are broadcast in cleartext. Meaning that they are visible to anyone located between your computer and the intended server destination.
For example, any curious person with a 802.11b-equipped laptop, a packet sniffer program (designed to intercept and interpret data broadcast across a network) and a rudimentary grasp of networking could sit within range of UMBC's wireless networks and grab any usernames and passwords transmitted in cleartext. Regardless of where and how you're online, if you use telnet or FTP, you're putting your vital data at risk.
Because of the vulnerabilities associated with telnet, UMBC's Office of Information Technology (OIT) will prohibit telnet connections to UMBC servers (such as research.umbc.edu and the gl server cluster) beginning in January, 2003.