About Telnet

Telecommunication network protocol, also known by the nickname "Telnet," can be used to access wide area (WAN) and local area (LAN) networks. A cross-platform protocol, Telnet can be used on a variety of server types, allowing remote access and execution of server commands. In previous years, Telnet was the preferred protocol for communication between the client and its server, largely due to its stable reputation and the lack of viable alternate technology. Though Telnet has been largely phased out as other, more secure protocols have been adopted, it remains in use today for remote server connections and its influence can still be seen in modern businesses, operating systems and the evolution of "geek" culture.

History of Telnet

Telnet formed its first roots in 1969, fashioned in early internet convention, giving users a way to access remote machines. With a fast and relatively easy command-line interface, the protocol became an official one in 1973. At that point, Telnet utilized 8-bit technology to send data encoded in American Standard Code for Information Interchange (ASCII) format. After revision and ensuing acknowledgment as the "new Telnet," the protocol was documented and accepted into widespread use in its modern form. Since then, common extensions to Telnet have become technological standards, and a host of other recommended extensions remain in use. During its early years, Telnet was used primarily by educational institutions, government agencies or large commercial operations. The dot-com boom of the 1990s ushered in an Internet Age which led the private sector to discover and use Telnet before security concerns combined with widespread use to make it much more obsolete.

Benefits of Telnet

Telnet's benefits extend far beyond standardizing connections, as it fosters execution of applications. Telnet's external interface operates on application-level, while its internal interfaces work with TCP for symmetric client and server roles. Telnet also works at standardizing terminals and is known as one of the most stable protocols of its kind. Telnet enables virtually real-time execution of commands by remote login, enabling off-site server manipulation and command execution.

Connection & Command Execution

Connection to a Telnet server is usually initiated by a client (user accessing a Telnet program on his or her terminal or computer). Web browsers alone cannot connect to Telnet servers. Once the program has been initiated, Telnet will give the user access to server programs. Simultaneous logins are generally supported. Regardless of their respective operating systems, users can access a program without problem on the Telnet server.

Telnet operates in both the application-editing input mode and the command mode, where instructions are sent to the server to execute. In general, Telnet servers are fairly user-friendly and sport well-documented support systems. Basic commands have short names and remain common to most Telnet servers, including "z" for suspending activity, "open" for establishing connections, "help" to access command lists and support documents, and "close" or "quit" to disconnect.

Telnet and Security Concerns

With the popularity of the Internet rising in the late 20th century, security issues concerning Telnet rose to the technology sector's attention. Server hacking created a strong need for high levels of encryption and made Telnet remote logins a risky affair. Because Telnet is essentially a data protocol without encryption, hackers can use routers, switches, hubs and gateways to intercept information easily in a form of high-tech eavesdropping and recording. Additionally, Telnet lacks the ability to take measures against such interception. These vulnerabilities have caused Telnet's use to drastically decrease, as SSH protocol offers similar functionality with better security. While Telnet extensions do remedy the issues, and perhaps even offer arguably better security through TLS and SASL authentication, they have not become popular or widely used in the wake of SSH.

Modern Telnet Uses

Despite its decline in everyday use, Telnet still remains functional today. Those troubleshooting network services will use Telnet for both debugging and diagnostic interaction between computers. Telnet is also used to provide large databases of information to the general public free of charge and to enable online multi-user games such as MUDs. Libraries throughout the United States use Telnet to allow the public access to their catalogs. Certain programs that are still commonly utilized online use Telnet protocol in order to operate, such as Archie, WAIS, Whois and Netfind. In the business sector, enterprise networks will use Telnet for commercial application hosting, networking, bulletin board systems (BBSs) and STN networks.