1.2.1.21.2 Telnet Server Configurations

Telnet Specific User Configurations

  • Maximum Connections:

    • Maximum number of Telnet connections
    • Default value: 2
    • Symbol TCPIP_TELNET_MAX_CONNECTIONS

  • Default Socket TX Buffer Size:

    • Size of the telnet socket TX buffer
    • If long messages are sent over the telnet connection the socket should have a large enough buffer to write the data at once
    • Leave 0 for default TCP TX buffer size
    • Default value: 0
    • Symbol TCPIP_TELNET_SKT_TX_BUFF_SIZE

  • Default Socket RX Buffer Size:

    • Size of the telnet socket RX buffer
    • If long messages are sent over the telnet connection the socket should have a large enough buffer to receive the data
    • Leave 0 for default TCP RX buffer size
    • Default value: 0
    • Symbol TCPIP_TELNET_SKT_RX_BUFF_SIZE

  • Telnet Server Listening Port:

    • Port on which the telnet server is listening
    • Default is TCPIP_TELNET_SERVER_PORT (23) or TCPIP_TELNET_SERVER_SECURE_PORT (992)
    • Adjust as needed
    • Default value: 23
    • Symbol TCPIP_TELNET_LISTEN_PORT

  • Telnet Task Rate (in msec):

    • Telnet task processing rate, in milliseconds.
    • The Telnet module will process a timer event with this rate for maintaining its own queues, processing timeouts, etc.
    • The lower the rate (higher the frequency) the higher the module priority and higher module performance can be obtained
    • The value cannot be lower than the TCPIP_STACK_TICK_RATE.
    • Default value: 100
    • Symbol TCPIP_TELNET_TASK_TICK_RATE

  • Size of the Internal Print Buffer:

    • Size of the internal print buffer
    • This buffer is used when the telnet console printf style function is called
    • Adjust based on the length of the messages to be formatted with print statements
    • This buffer is created in the automatic stack.
    • Make sure that there is enough stack space for this buffer!
    • Default value: 200
    • Symbol TCPIP_TELNET_PRINT_BUFF_SIZE

  • Size of the Internal Line Buffer:

    • Size of the internal line buffer
    • This buffer is used for receiving and assembling the password, authentication and regular characters
    • Adjust based on the length of the commands sent to the telnet server
    • This buffer is created in the automatic stack.
    • Make sure that there is enough stack space for this buffer!
    • Default value: 80
    • Symbol TCPIP_TELNET_LINE_BUFF_SIZE

  • Size of the Internal User Name Buffer:

    • Maximum size of the internal buffer to store the user name
    • Adjust based on the length of the user names allowed for the telnet connections
    • A buffer of this size if allocated for each connection to store the login user name
    • Longer user names will be truncated to this size
    • Default value: 15
    • Symbol TCPIP_TELNET_USERNAME_SIZE

  • Create Telnet Sockets with NO-DELAY option:

    • Create the telnet sockets with NO_DELAY option
    • Default value: false
    • Symbol TCPIP_TELNET_CONFIG_FLAG_NO_DELAY, TCPIP_TELNET_FLAG_NO_DELAY

  • Pass Control Characters to Console:

    • Pass the telnet commands, options, controls, etc. within the messages to the console
    • By default they are removed and only printable characters are sent to the console
    • Enable only for debug or special purposes.
    • Default value: false
    • Symbol TCPIP_TELNET_CONFIG_PASS_CONTROL_CHARS, TCPIP_TELNET_FLAG_PASS_CONTROL_CHARS

  • Select telnet Authentication:

    • Select the type of telnet authentication: run time or build time (obsolete)

    • Runtime authentication: this is the default and the PREFERRED case!

      • The telnet module will call a registrated callback to authenticate the users.
      • It is the preferred authentication method.
      • It requires the run time registration of an authentication handler
      • Until the moment the authentication handler is registered any login attempts will fail!

    • The old OBSOLETE build time authentication method

      • TCPIP_TELNET_USERNAME and TCPIP_TELNET_PASSWORD is used
      • This method is DEPRECATED and it will be eventually removed!
      • It is recommended that you leave the setting to false!

    • Note: the build time authentication stores the telnet user and password in clear in the code and it should be avoided!

    • Default value: false (Run time Authentication)

    • Symbol TCPIP_TELNET_OBSOLETE_AUTHENTICATION, TCPIP_TELNET_AUTH_CONFIG

  • Connection Info Used for Authentication:

    • The connection info is passed to the authentication handler
    • The handler has access at data showing which IP address requested the connection
    • Used only for run time authentication
    • If false no connection info data is provided to the authentication callback
      • This is useful for the default case when all connections will use the same username/password.
    • If true the authentication callback will contain the connection info data to allow different processing based on the source of the authentication request
    • Note: This flag is relevant only when TCPIP_TELNET_OBSOLETE_AUTHENTICATION == false
    • Default value: true
    • Symbol TCPIP_TELNET_AUTHENTICATION_CONN_INFO

  • User Name:

    • Default Telnet user name
    • DEPRECATED. This is used only when there is no authentication callback defined!
    • Use only when TCPIP_TELNET_OBSOLETE_AUTHENTICATION == true
    • Default value: "admin"
    • Symbol TCPIP_TELNET_USERNAME

  • Password:

    • Default Telnet password
    • DEPRECATED. This is used only when there is no authentication callback defined!
    • Use only when TCPIP_TELNET_OBSOLETE_AUTHENTICATION == true
    • Default value: "microchip"
    • Symbol TCPIP_TELNET_PASSWORD