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About Telnet

The ESP has a raw tcp server that can be used to execute commands. It called Telnet even it is not a real telnet protocol. It behaves like serial port, you can send commands ending by \n and receive the response.

The raw tcp protocol does not support any authentication, but if authentication is enabled, you must use any ESPXXX command with appropriate password to authenticate the connection during the first connection. Other commands will be executed only after the authentication is done. You won’t need to authenticate again for additional commands until you disconnect.

  • The Telnet server is enabled by default and listen on port 23. Be sure #define TELNET_FEATURE is defined in configuration.h

  • You can configure the Telnet following settings:

NameDescriptionMethod
Enable TelnetEnable or disable the Telnet serverWebUI or ESP command
Telnet portThe port used by the Telnet serverWebUI or ESP command
Telnet user passwordUser level passwordWebUI or ESP command
Telnet admin passwordAdmin level passwordWebUI or ESP command
  • You can also disable the welcome message that is displayed when the client connects to the Telnet server if it cause any issue with your client application.

    In configuration.h just uncomment the following line to enable the Telnet server: #define DISABLE_TELNET_WELCOME_MESSAGE