# Debian Server Setup

Here's the minimum setup I put on my Debian 12 Bookworm servers.

## System configuration

```
# system updates
sudo apt update
sudo apt install -y openssh-server mosh ufw vim
sudo apt upgrade -y
sudo apt autoremove -y
# use Vim
sudo update-alternatives --config editor
# OpenSSH & Mosh & UFW
sudo groupadd --system ssh-users
sudo usermod -aG ssh-users $(whoami)
sudo cp /etc/ssh/sshd_config /etc/ssh/sshd_config.bak
sudo wget \
	https://git.duckduckwhale.com/DuckDuckWhale/dotfiles/raw/branch/main/system/sshd/sshd_config-debian \
	-O /etc/ssh/sshd_config
sudo systemctl enable ssh --now
sudo systemctl reload ssh
sudo ufw limit OpenSSH # sudo ufw limit 22/tcp
sudo ufw allow mosh # sudo ufw allow 60001:60999/udp # mosh profile includes unused 60000 & 61000
sudo ufw enable
# sanity check
systemctl status ssh
sudo ufw status
su - $(whoami)
# apply all settings
sudo reboot
```

## User SSH keys

```
mkdir -p ~/.ssh
chmod 700 ~/.ssh
# insert your SSH public keys into the file
touch ~/.ssh/authorized_keys
chmod 600 ~/.ssh/authorized_keys
```