How to ssh windows to linux

This tutorial is going to show you 3 ways to log into Linux server on Windows via SSH.

What’s SSH?

SSH stands for Secure Shell, which was invented in 1995 to replace the insecure Telnet (Telecommunication Network). It’s now the primary way for system administrators to securely log into remote Linux servers over the public Internet. Although it looks and acts the same as Telnet, all communications over the SSH protocol is encrypted to prevent packet sniffing.

If you are running a Linux or Mac computer, SSH client is installed by default. You can open up a terminal window and run the ssh command like below to connect to a remote Linux server.

ssh [email protected]

Now let’s discuss how to use SSH on Windows.

Method 1: Windows 10’s Built-in SSH Client

The Microsoft PowerShell team decided to port OpenSSH (both the client and the server) to Windows in 2015. It finally arrived in Windows 10’s Fall Creator Update in 2017 and is enabled by default in the April 2018 Update.

To use the OpenSSH client on Windows 10, simply open a PowerShell window or a command prompt window and run the ssh command.  For example, if I want to connect to my Ubuntu desktop in the LAN, I would run

ssh [email protected]

linuxbabe is the username on my Ubuntu desktop and 192.168.0.101 is the private IP address for my Ubuntu desktop. The first time you connect to a Linux computer, you will be prompted to accept the host key. Then enter your password to login. After login, you can run Linux commands to do administrative tasks.

Note that if you want to paste a password into the PowerShell window, you need to right-click the mouse and press Enter.

Картинка с сайта: www.linuxbabe.com

To log out from the Linux box, run the exit command or press Ctrl+D.

The default font size in PowerShell Window is very small. To change it, right-click the titlebar and select properties, then you can change the font size, and the background color.

Картинка с сайта: www.linuxbabe.com

Method 2: Use SSH in Windows Subsystem for Linux

Windows Subsystem for Linux (WSL) enables you to run native Linux command-line tools directly on Windows 10. If you are a system administrator, WSL is probably an overkill for just using SSH because it would install and run a Linux distro (without graphical user interface) on your Windows 10 desktop. WSL is created for web developers or those who need to work on open-source projects. You can use not only SSH but also other Linux command line tools (Bash, sed, awk, etc).

Open the Microsoft Store and enter WSL in the search box. Select Run Linux on Windows and install a Linux distro of your choice.

Картинка с сайта: www.linuxbabe.com

For example, I choose Ubuntu and click the Get button to install it.

Картинка с сайта: www.linuxbabe.com

Once your Linux distro is installed, open the Control Panel and select Programs -> Turn Windows features on or off. Tick on the checkbox of Windows Subsystem for Linux to enable this feature. (You may need to reboot your Windows PC for this change to take effect.)

Next, you can launch the Linux distro from the start menu by search the distro’s name. The first time you launch it, you need to create a user and set a password.

Картинка с сайта: www.linuxbabe.com

After that, you can use the ssh command like below to connect to a Linux server or PC that runs a SSH server.

ssh [email protected]

Method 3: Use Putty

Putty is a well-known and the most popular SSH client on Windows before the arrival of Windows OpenSSH client and Windows Subsystem for Linux. To use SSH with Putty, you need to download the Putty program from the official website and install it.

Launch Putty from the Start menu. Then enter the IP address or hostname of the Linux box and click the Open button to connect to it.

Картинка с сайта: www.linuxbabe.com

Accept the host key and you will be prompted to enter the username and password.

Картинка с сайта: www.linuxbabe.com

Please note that when you type in your password, the cursor doesn’t move, but it’s actually accepting your password.  To paste text into Putty, first press Ctrl+C to copy the text, then go to Putty window and press the right button of your mouse.

How to Set Up SSH Key on Windows 10 (Optional)

There’re mainly two ways of authenticating user login with OpenSSH server:

• password authentication
• public-key authentication: also known as passwordless SSH login because you don’t need to enter your password.

To set up public-key authentication on Windows 10, follow the instructions below.

Open Windows Powershell, and run the following command to generate SSH keypair.

ssh-keygen -t rsa -b 4096

Where:

• -t stands for type. The above command generates an RSA type keypair. RSA is the default type.
• -b stands for bits. By default, the key is 3072 bits long. We use a 4096 bits key for stronger security.

When asked which file to save the key, you can simply press Enter to use the default file. Next, you can enter a passphrase to encrypt the private key, but you will need to enter this passphrase every time when you log into the Linux server. If you don’t want it, you can press Enter, so it will have no passphrase.

Картинка с сайта: www.linuxbabe.com

• The private key (your identification) will be saved in the .ssh/id_rsa file under your user directory.
• The public key will be saved in the .ssh/id_rsa.pub file.

Now we need to upload the public key to remote Linux server. You can display the public key in the Powershell with the following command.

cat .ssh/id_rsa.pub

Then log in to your server via password authentication, and run the following command to create a .ssh directory under your home directory.

sudo mkdir ~/.ssh

Create the authorized_hosts file

sudo nano ~/.ssh/authorized_keys

Copy your SSH public key and paste it to this file. Save and close the file. To save a file in Nano text editor, press Ctrl+O, then press Enter to confirm. To close a file, press Ctrl+X.

Next, change the permission of this file.

sudo chmod 600 ~/.ssh/authorized_keys

Log out of your Linux server.

exit

Now you can SSH into your server without entering a password.

Next Step

I hope this article helped you use SSH on Windows. You might also want to protect SSH service from hacking, I recommend setting up public-key authentication or two-factor authentication.

• 2 Simple Steps to Set up Passwordless SSH Login on Ubuntu
• Set Up SSH Two-Factor Authentication (2FA) on Ubuntu Server

Also, you can enable automatic security updates on your Linux server to patch vulnerabilities.

• Set Up Automatic Security Update (Unattended Upgrades) on Ubuntu

If you want FTP access to the Ubuntu server, you can set up pure-FTPd server.

• How to Set Up a Secure FTP Server with Pure-FTPd on Ubuntu

As always, if you found this post useful, then subscribe to our free newsletter to get more tips and tricks. Take care 🙂

The secure shell protocol (SSH) is the most common method for controlling remote machines over the command line in the Linux world. SSH is a true Linux original, and it is also gaining popularity in the Windows world. There is even official Windows documentation for SSH, which covers controlling Windows machines using OpenSSH.

This article describes how to establish an SSH connection from a Windows machine to a Fedora 33 Linux system using the popular open source tool PuTTY.

Ways to use SSH

SSH uses a client-server architecture, where an SSH client establishes a connection to an SSH server. The SSH server is usually running as a system daemon, so it is often called SSHD. You can hardly find a Linux distribution that does not come with the SSH daemon. In Fedora 33, the SSH daemon is installed but not activated.

You can use SSH to control almost any Linux machine, whether it’s running as a virtual machine or as a physical device on your network. A common use case is the headless configuration of embedded devices, including the Raspberry Pi. SSH can also be used to tunnel other network services. Because SSH traffic is encrypted, you can use SSH as a transport layer for any protocol that does not provide encryption by default.

In this article, I’ll explain four ways to use SSH: 1. how to configure the SSH daemon on the Linux side, 2. how to set up a remote console connection, 3. how to copy files over the network, and 4. how to tunnel a certain protocol over SSH.

1. Configure SSHD

The Linux system (Fedora 33 in my case) acts as the SSH server that allows the PuTTY SSH client to connect. First, check the daemon’s SSH configuration. The configuration file is located at /etc/ssh/sshd_config and contains a lot of switches that can be activated by commenting out related lines:

#	$OpenBSD: sshd_config,v 1.100 2016/08/15 12:32:04 naddy Exp $

# This is the sshd server system-wide configuration file.  See
# sshd_config(5) for more information.

# This sshd was compiled with PATH=/usr/local/sbin:/usr/sbin:/sbin:/usr/local/bin:/usr/bin:/bin

# The strategy used for options in the default sshd_config shipped with
# OpenSSH is to specify options with their default value where
# possible, but leave them commented.  Uncommented options override the
# default value.

Include /etc/ssh/sshd_config.d/*.conf

#Port 22
#AddressFamily any
#ListenAddress 0.0.0.0
#ListenAddress ::

The default configuration, where no line is uncommented, should work for this example. Check whether the SSH daemon is already running by typing systemctl status sshd:

$ systemctl status sshd
● sshd.service - OpenSSH server daemon
   Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor preset: enabled)
   Active: active (running) since Fri 2018-06-22 11:12:05 UTC; 2 years 11 months ago
     Docs: man:sshd(8)
           man:sshd_config(5)
 Main PID: 577 (sshd)
    Tasks: 1 (limit: 26213)
   CGroup: /system.slice/sshd.service
           └─577 /usr/sbin/sshd -D -oCiphers=aes256-gcm@openssh.com,chacha20-[...]

If it’s inactive, start it with the systemctl start sshd command.

2. Set up a remote console

On Windows, download the PuTTY installer, then install and open it. You should see a window like this:

Картинка с сайта: opensource.com

In the Host Name (or IP address) input field, enter the connection information for your Linux system. In this example, I set up a Fedora 33 virtual machine with a bridged network adapter that I can use to contact the system at the IP address 192.168.1.60. Click Open, and a window like this should open:

This is an SSH security mechanism to prevent a man-in-the-middle attack. The fingerprint in the message should match the key on the Linux system at /etc/ssh/ssh_host_ed25519_key.pub.. PuTTY prints the key as an MD5 hash. To check its authenticity, switch to the Linux system, open a command shell, and enter:

ssh-keygen -l -E md5 -f /etc/ssh/ssh_host_ed25519_key.pub

The output should match the fingerprint shown by PuTTY:

$ ssh-keygen -l -E md5 -f /etc/ssh/ssh_host_ed25519_key.pub
256 MD5:E4:5F:01:05:D0:F7:DC:A6:32 no comment (ED25519)

Confirm the PuTTY Security Alert by clicking Yes. The host system’s fingerprint is now in PuTTYs trust list, which is located in the Windows registry under:

HKEY_CURRENT_USER\SOFTWARE\SimonTatham\PuTTY\SshHostKeys

Enter your correct login credentials, and you should be on the console in your home directory:

Картинка с сайта: opensource.com

3. Copy files over the network

In addition to the remote console, you can use PuTTY to transfer files via SSH. Look in the installation folder under C:\\Program Files (x86)\\PuTTY and find pscp.exe. You can use this to copy files to and from a Linux system.

Open a command prompt with Windows + R and enter cmd. Copy the file MyFile.txt from your Linux user home directory to your Windows home directory by entering:

C:\"Program Files (x86)"\PuTTY\pscp.exe stephan@192.168.1.60:/home/stephan/MyFile.txt .

To copy a file from the Windows home directory to the Linux user home directory, enter:

C:\"Program Files (x86)"\PuTTY\pscp.exe MyFile.txt stephan@192.168.1.60:/home/stephan/

As you may have already figured out, the copy command’s general structure is:

pscp.exe <source> <target>

4. Tunnel a protocol

Imagine you have a Linux machine that is running an HTTP-based service for some arbitrary application. You want to access this HTTP service from your Windows machine over the internet. Of course, you cannot expose the related TCP port to the public because:

1. The server is running HTTP, not HTTPS
2. There is no user management nor login at all

At first glance, it looks like an impossible task to set up this architecture without producing a horrible security flaw. But SSH makes it relatively easy to set up a safe solution for this scenario.

I will demonstrate this procedure with my software project Pythonic. Running as a container, Pythonic exposes two TCP ports: TCP port 7000 (main editor) and TCP port 8000 (the code-server source-code editor).

To install Pythonic on a Linux machine, run:

podman pull pythonicautomation/pythonic
podman run -d -p 7000:7000 -p 8000:8000 pythonic

Switch to your Windows machine, open PuTTY, and navigate to Connection -> SSH -> Tunnels. Add the two TCP ports you want to forward:

• Source: 7000 / Destination: localhost:7000
• Source: 8000 / Destination: localhost:8000

Картинка с сайта: opensource.com

Then go back to the Session section, and establish an SSH connection as you did before. Open a browser and navigate to https://localhost:7000; you should see a screen like this:

Картинка с сайта: opensource.com

You have successfully configured port forwarding!

Warning: If you expose TCP Port 22 to the public, don’t use easy-to-guess login credentials. You will receive login attempts from all over the world trying to access your Linux machine with common, standard credentials. Instead, permit only known clients to log in. This login restriction can be achieved using public-key cryptography, which uses a key pair in which the public key is stored on the SSH host machine, and the private key remains at the client.

Debugging

If you are struggling to connect to your Linux machine, you can follow the processes in your SSH daemon with:

journalctl -f -u sshd

This is how an ordinary log-in process looks like with LogLevel DEBUG :

Картинка с сайта: opensource.com

Learn more

This article barely scratched the surface about ways to use SSH. If you are looking for information about a specific use case, you can probably find it among the tons of SSH tutorials on the internet. I use PuTTY heavily at work because its easy configuration and good interoperability between operating systems make it a Swiss Army knife tool for connectivity solutions.

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