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