Hacker News Reader

Comment by teddyh | Hacker News Reader

Note: Some server motherboards also have a setting in the BIOS to show boot-time text, and allow BIOS configuration, on a serial port.

View on HN

Not only server. If you have a Q-series desktop motherboard with AMT you can enable Serial-Over-Lan and access the machine remotely (and power on/off or reset it as well). Q series chipsets are also found on Fujitsu/Dell/HP prebuilts which can be picked up quite cheaply when companies decide to upgrade. For servers you usually have IPMI/iDrac etc. which uses more power, but usually has a better (web)interface.

Yep. I've just picked up a few second hand HP EliteDesk 800 G2 desktops with the intention of turning them into a homelab for k8s learning. They have AMT and the web power control, VNC based KVM and SoL work well.

There is no BIOS serial redirection, so SoL is no use until the OS starts booting, and grub has a bug[0][1][2] which means it can't find the AMT SoL when booting in EFI mode. But SoL works fine as soon as the kernel starts, and the KVM VNC works fine during BIOS and GRUB if I have an emergency.

One gotcha which would catch someone out who wasn't expecting it - the onboard video disables itself when no monitor is connected, so the AMT KVM just shows a black screen. This can be solved by DisplayPort or VGA "ghost" dongle in the back of the machine to talk EDID and pretend to be a screen.

I'm a big fan of conserver, and intend to use it in this project to spawn amtterm processes to connect to the SoL ports.

0: https://savannah.gnu.org/bugs/?42026

1: https://community.intel.com/t5/Intel-vPro-Platform/No-AMT-se...

2: https://wiki.networksecuritytoolkit.org/index.php/HowTo_Head...

... and, if you don't have Serial-over-LAN (SOL) access via IPMI, etc., you can always just wire the serial port up to another host to give yourself access to that serial port remotely.

Then, just SSH in to the other host and use something like "minicom" to connect directly to the serial port -- or use "conserver" (mentioned in TFA) when you've got multiple consoles and/or multiple users to deal with simultaneously.

Plenty of HN'ers are all-in on "cloud" but for anyone dealing with physical devices (routers, servers, whatever), remote access to the console can be a lifesaver at times!

For a minimal serial-port access program, I usually prefer the classic cu(1) (originally a part of the UUCP program suite); miniterm is basically an old-DOS-style program in the same vein as Telix or PC-Talk, and is generally too heavyweight for my purposes.

Reply on news.ycombinator.com