The development of the Internet has seen many systems and applications become obsolete over the years, but there some tools that survive the culling even as newer, more advanced technology is developed. Much of the Internet is still overlayed on technology that can be traced back to the infancy of networking. Telnet (Telecommunication network) protocol and is an excellent example.
Telnet Servers go right back to the beginning. Now, most of our networking applications are run based on TCP (Transmission Control Protocol) and Telent connections do, now, work through TCP as well, but when it was first developed it was designed based on the earlier NCP (Network Control Program) model. TCP rendered the old system obsolete, as it is generally more versatile. The core improvement is that TCP allows for bidirectional, rather than unidirectional, information flow.
Telnet survived the threat of obsolescence, however, and continued to evolve and was adapted to TCP networks. The main use of the Telnet client is to exercise remote control over Telnet enabled servers. Telnet was commonly used in the early days of the Internet when security wasn’t such an issue. Originally, most computers and the vast majority of networks were the property of universities, research institutes and government agencies. Neither the technological know-how nor the necessary equipment to hack into a network was widely available and Telnet was originally developed in this context. Consequently, it still has many weaknesses from a security perspective. The protocol is not innately setup to encrypt data sent through a network and, therefore, any host along the network chain setup to listen for the information packets can intercept and read any information sent using Telnet. The simplicity and versatility of the system means that it is still used, but generally only on isolated networks.
Telnet is often still used for communication between workstations and a mainframe. The protocol enables the remote operation of applications on a host machine, which makes it ideal for systems designed for multitasked machines whose applications all use a common database. Another contemporary application is in network diagnostics. Due to the relative simplicity of the protocol it can be useful for testing the connectivity between servers and clients to isolate any problems before proceeding to identify more complex configuration issues. Telnet is also still used to implement remote access to databases that do not require security, such as read-only databases that are publicly available, as in the case of library catalogues.
Finally, gamers keep the old traditions alive. Telnet made the first MUD (Multi-User Dungeon) games possible and, even though modern graphics have outstripped those in old games, they still remain popular among diehards.