Makefile

# name of your application
APPLICATION = telnet_server

# If no BOARD is found in the environment, use this default:
BOARD ?= native

# This has to be the absolute path to the RIOT base directory:
RIOTBASE ?= $(CURDIR)/../..

# Include packages that pull up and auto-init the link layer.
# NOTE: 6LoWPAN will be included if IEEE802.15.4 devices are present
USEMODULE += netdev_default

# use GNRC by default
LWIP ?= 0

ifeq (0,$(LWIP))
  USEMODULE += auto_init_gnrc_netif
  # Activate ICMPv6 error messages
  USEMODULE += gnrc_icmpv6_error
  # Specify the mandatory networking modules for IPv6
  USEMODULE += gnrc_ipv6_default
  # Additional networking modules that can be dropped if not needed
  USEMODULE += gnrc_icmpv6_echo
else
  USEMODULE += lwip_ipv6
endif

USEMODULE += netutils
# Add also the shell, some shell commands
USEMODULE += shell
USEMODULE += shell_cmds_default
USEMODULE += ps
# Include the telnet server
USEMODULE += stdio_telnet

# Enable faster re-connects
CFLAGS += -DCONFIG_GNRC_TCP_EXPERIMENTAL_DYN_MSL_EN=1

# Acknowledge that telnet is bad
I_UNDERSTAND_THAT_TELNET_IS_INSECURE = 1

# enable debug output via UART
FEATURES_OPTIONAL += periph_uart

# Optionally include DNS support. This includes resolution of names at an
# upstream DNS server and the handling of RDNSS options in Router Advertisements
# to auto-configure that upstream DNS server.
# USEMODULE += sock_dns              # include DNS client
# USEMODULE += gnrc_ipv6_nib_dns     # include RDNSS option handling

# Comment this out to disable code in RIOT that does safety checking
# which is not needed in a production environment but helps in the
# development process:
DEVELHELP ?= 1

include $(RIOTBASE)/Makefile.include

# Set a custom channel if needed
include $(RIOTMAKE)/default-radio-settings.inc.mk