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FreeBSD Serial Over LAN

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In a past post I showed how easy it was to setup IPMI support on FreeBSD this post goes one step further and shows how to configure SOL.

First you need to ensure that kernel has the uart device compiled in which is simply the following in your kernel config
device uart

Next you need to configure your console to support the settings of your IPMI in /boot/loader.conf. In our case that’s a built in Supermicro IPMI which is configured on serial port two with the default settings

# SOL console
boot_multicons="yes"
boot_serial="YES"
console="comconsole,vidconsole"
comconsole_speed="115200"
comconsole_port="0x2f8"
hint.uart.0.flags="0x00"
hint.uart.1.flags="0x30"
loader_color="NO"

Next edit /etc/ttys to enable console over serial port two

ttyu1   "/usr/libexec/getty std.115200" vt100   on secure

Finally to connect to your configured SOL use ipmitool

ipmitool -I lanplus -H <hostname> -U <username> -P <password> sol activate

Hardware Quirks

  • On some older Supermicro hardware where serial ports can be disabled while still keeping SOL active, it was necessary to disable the serial port to ensure the port speed didn’t drop to 19.2 during the kernel phase.
  • On some older Supermicro hardware the IPMI module advertised USB 2.0 speeds but only worked reliably at 1.0 speeds so it was necessary to add the disable high speed mode in loader.conf with hw.usb.ehci.no_hs=”1″
  • For X10SLD-F/HF (Intel 1150-based Microcloud), the same settings work (com3 despite MB has no com2) but also loader_color=”NO” is needed; otherwise, loader resets to black-on-black before invoking the kernel. (Thanks to Dmitry Morozovsk)
  • On some newer Supermicro Hardware we also needed to enable Serial Port Out-Of-Band Management for SOL to work after the boot loader (once the kernel had taken over).
  • If your comm port differs you can use loader.conf to set it e.g. com 3: comconsole_port=”0x3E8″
  • Limiting the console uart via loader.conf can also help e.g. hw.uart.console=1234
  • Some have reported configuring the console board rate via loader.conf e.g. hw.uart.console=”br:9600″

More information on what the settings mean and how to configure serial support for other configs can be found in the FreeBSD Handbook – Serial Console Setup

Hints and tips from other users experiences can be found here: SuperMicro IPMI/SOL and ipmitool troubles

Update: 23-05-2016 – Added comconsole_port and loader_color to the default config set which fixes incorrect choice of console port and black on black text.

Written by Dilbert

December 9th, 2012 at 9:02 pm

Posted in FreeBSD

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