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---
title: "Adventures on server setup without a monitor"
date: 2024-11-18T21:41:35-08:00
tags: ["networking"]
ShowToc: false
---
# TL;DR
What happens when you forget to statically assign an IP address to a server running `NetworkManager` or `systemd-netword` or even Debian's default networking setup?
It won't have network connection until IP assigned (because the subnet doesn't have a DHCP in router for example), so no SSH.
But you also don't have access to video output.
Instead of typing into the TTY hoping for the best, all 3 of the aforementioned systems default to DHCP, and _there is nothing saying a DHCP server has to be running on the router or gateway_.
So, just install and configure `kea` (or a DHCP server of your choice) on any other computer on the network, reboot the server in question, and voilà!
SSH to your hearts content.
# The story
So the story goes like this.
I recently got hands on a nice little old desktop tower, plenty of RAM and a good number of SATA ports for selfhosting: Seafile, Immich and what not.
Now it _is_ rather old machine, with only VGA and DVI on the motherboard. This means my little trusty HDMI to USB video capture dongle won't be helpful!
I also need to deploy this machine to my parent's house, for I plan on giving them access to a photo backup solution.
I need to bring a monitor that has a VGA port on it.
So I at the comfort of my home, I took some time to install Debian, as well as all other packages I could possibly need. Also configured a SSH key.
## Uh oh
And as all good stories go, the _one thing_ I was supposed to do was not done: no monitor, no way to see what's happening on screen to configure its WiFi connection properly.
No network, no SSH-ing either.
For reasons beyond the topic of this story, my parents' router does not have an DHCP server running if connected to the ethernet ports.
I _have_ to connect WiFi or manually set a static IP on the `eth0` interface.
Quickly, I thought "what if I could just type out all the commands without a monitor?"
Trying to open vim on `/etc/network/interfaces` and blindly modifying a complex configuration file obviously did not work so well.
Although I did figure out one helpful tidbit: since this machine has a beeper, I can run things like `foobar && tput bel` in TTY to get an audio confirmation that something succeeded.
After ten minutes of desparately trying various commands and questioning if I had been making typos all along, an enlightenment suddenly found its way into my mind: nothing is stopping me from running an ad-hoc DHCP server just for this purpose!
[Kea](https://www.isc.org/kea/) is apparently the recommended implementation, so I installed it on my laptop, and after some fiddling of configs per https://wiki.archlinux.org/title/Kea (because ArchWiki is the one wiki to rule them all), it did work. The server allocates the first address in the pool, so I just picked `192.168.233.1/16` and successfully SSH-ed in.
No need to drive 30 minutes round trip to get my VGA monitor!
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