telnet
Connect to remote systems using Telnet protocol
TLDR
Telnet to the default port of a host
Telnet to a specific port of a host
Exit a telnet session
Emit the default escape character combination for terminating the session
Start telnet with "x" as the session termination character
Telnet to Star Wars animation
SYNOPSIS
telnet [hostname|IP address] [port]
PARAMETERS
hostname|IP address
The hostname or IP address of the remote machine to connect to.
port
The port number to connect to on the remote host (default is 23).
DESCRIPTION
Telnet is a user command and underlying TCP/IP protocol for accessing remote computers. Through telnet, an administrator or another user can access someone else's computer remotely. Telnet is a client-server protocol, where the telnet client runs on your machine and connects to a telnet server running on a remote system.
It allows you to establish a terminal session on another host. However, it transmits data in plaintext, making it inherently insecure, particularly for password exchange. Therefore, its use is generally discouraged, especially over untrusted networks like the internet. Alternatives like SSH are widely preferred due to their encryption capabilities.
CAVEATS
Telnet transmits data in plaintext, making it extremely vulnerable to eavesdropping. Do not use Telnet over public networks. Use SSH instead.
SECURITY CONSIDERATIONS
The most significant drawback of Telnet is its lack of encryption. All data, including usernames and passwords, are transmitted in clear text. This makes it easy for attackers to intercept sensitive information using packet sniffing tools. Because of this vulnerability, Telnet should not be used unless absolutely necessary and only over trusted networks.
COMMON USAGE (HISTORICAL)
Historically, Telnet was used for a variety of tasks, including:
Remote system administration: Connecting to servers to configure settings or troubleshoot issues.
Accessing online resources: Connecting to public terminals or BBS systems.
Testing network services: Checking if a service is listening on a specific port. This has largely been replaced by tools like `netcat`.
HISTORY
Telnet was one of the earliest internet protocols and was widely used for remote access and administration. However, due to its lack of security, its usage has declined significantly with the rise of secure alternatives like SSH. Telnet was standardized in 1969 by the IETF and updated through various RFCs. Today it's rarely enabled by default. The rise of SSH has marked the decline of Telnet.