Linode/Setup
Assuming you have made a Linode with Debian 11.
User accounts
- Make user accounts. (You can do this as many times as you want to add more users.)
adduser \
--system \
--shell /bin/bash \
--gecos 'User Description If u want' \
--group \
--home /home/USERNAME \
USERNAME
- Add user to
sudo
group (if needed)
usermod -aG sudo USERNAME
Security (only need to do this at setup)
Add cryptographic public keys for user authentication
- RSA keys (has known vulnerabilities)
- ed25519 keys (better alternative: faster, more secure, resilient against hash-function collision attacks, shorter)
Configure sshd
- Disable password login
- Disable root login
- Restart ssh otherwise the changes to sshd don't take effect!
service ssh restart
Setting up an SMTP server
By default, Linode disables SMTP ports 587 etc. This requires a manual human-facing support ticket to remove. (Done by @Jonny on Nov 25 2022)