SSH basics

Turn on SSH on a computer

Enable the SSH server on Linux, a Raspberry Pi, macOS or Windows, and find the address to connect to.

Turn on the SSH server

Ubuntu / Debian

Update and install. Run:

sudo apt update && sudo apt install openssh-server

Enable the service.
```
sudo systemctl enable --now ssh
```
Allow through firewall (if ufw is on).
```
sudo ufw allow OpenSSH
```
Check it worked.
```
systemctl status ssh
```

Fedora

Install and enable.

sudo dnf install openssh-server
sudo systemctl enable --now sshd

Open firewall.

sudo firewall-cmd --permanent --add-service=ssh
sudo firewall-cmd --reload

Arch

Install and enable.

sudo pacman -S openssh
sudo systemctl enable --now sshd

Raspberry Pi OS

When writing the SD card:
In Raspberry Pi Imager, open OS customisation settings, go to Services tab, tick Enable SSH, and set a username and password.

On a running Pi:

Use raspi-config: run sudo raspi-config, then Interface Options, SSH, Yes.
Or directly:
```
sudo systemctl enable --now ssh
```

macOS

Open System Settings > General > Sharing.
Turn on Remote Login. Click the info icon next to it to choose which users may log in.
- Or from Terminal:
```
sudo systemsetup -setremotelogin on
```

Windows

Go to Settings > System > Optional features > Add a feature.
Search for OpenSSH Server and install it.
Open PowerShell as Administrator and run:
```
Start-Service sshd
Set-Service -Name sshd -StartupType 'Automatic'
```
The installation automatically adds a firewall rule for port 22.

Alternative command-line install:
```
Add-WindowsCapability -Online -Name OpenSSH.Server~~~~0.0.1.0
```

Find the address and username

Linux

Address:
Run hostname -I - the first address is your IP. Or use ip -4 addr.

Username:
Run whoami.

macOS

Address:
Go to System Settings > Wi-Fi, click Details next to your network. Or in Terminal: ipconfig getifaddr en0.
The Remote Login pane also shows ssh user@address.

Username:
Run whoami.

Windows

Address:
Open Command Prompt and type ipconfig. Look for IPv4 Address under your active network adapter.

Username:
Run whoami and use the part after the backslash. With a Microsoft account, the username is the folder name under C:\Users and the password is the Microsoft account password.

Connect from Termphin

Open Termphin. You see the empty machine list.
Enter user@address. Type your username and the IP address in the user@host field (e.g. [email protected]). Tap +.
Choose authentication. Under Authentication, select Password. Tap Save, then tap the machine. When prompted, accept the host key.

Now you are connected. Next: switch to SSH keys for passwordless login, or harden the server.