Version 4 (modified by stappers, 2 years ago) (diff)

kernel boot parameter , netcat command

DebWrt Netconsole

DebWrt by default includes netconsole for devices with no normal serial interface. With netconsole it is possible to have all kernel boot messages ( not the messages from init and initscripts! ) forwarded over the network to a remote computer. eth0 is used as interface to forward messages from. Note that eth0 may vary from device to device.

Settings

Configuration is done by kernel boot parameter with 

netconsole=6665@192.168.1.1/eth0,6666@192.168.1.2/

That means

  • Embedded device: 6665@192.168.1.1/eth0
    • device eth0
    • address 192.168.1.1
    • port 6665
  • Remote computer: 6666@192.168.1.2
    • address 192.168.1.2
    • port 6666

The kernel boot parameter netconsole is defined during make menuconfig as part of CONFIG_CMDLINE.

Remote computer setup

  • configure the LAN port on the remote computer connected to the eth0 on the device with:
    • ip: 192,.168.1.2
    • netmask: 255.255.255.0
    • no default gw
  • use netcat to listen for UDP packets on port 6666 and dump contents to the console 
    nc -l -p 6666 -u