Installing the Microsoft-provided SSH server software on a Windows 11 system

Microsoft provides Secure Shell (SSH) server software with Windows 11 that you can use to listen for connections from remote SSH clients, but the server service is not installed by default. To install the Microsoft-provided SSH server software on a Windows 11 system, take the following steps:

1. Type optional features in the Windows Search field at the bottom of the screen and hit Enter, then click on "Open" when it is found.
2. Click on the View features button.
3. Scroll down the list of optional features until you see Open SSH Server and then click on the check box for it and click on the Next button.
4. Click on the Add button to add the OpenSSH Server capability to the system.
5. When the Optional features window shows that the OpenSSH Server software has been added, you can close the window. If you scroll down the list of added features before closing the window, you should see OpenSSH Server below OpenSSH Client.

After installing the software, you will need to start the OpenSSH server service.

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Viewing network connections on a Microsoft Windows system by protocol

If you just wish to see TCP ports in use on a Microsoft Windows system, you can issue the netstat -a -p TCP command at a command prompt. The -a parameter specifies all connections and listening ports should be displayed while the -p parameter can be used to select a protocol from TCP, UDP, TCPv6, or UDPv6. If used with the -s option to display per-protocol statistics, the protocol argument may be any of: IP, IPv6, ICMP, ICMPv6, TCP, TCPv6, UDP, or UDPv6. If you only wish to view IPv6 TCP ports in use, you can use netstat -a -p TCPv6. If you only wish to see currently established connections, you can pipe the output of the netstat command to the find command. E.g., netstat -a -p TCP | find "ESTABLISHED". Or, if you wished to see all of the TCP ports on which the system was listening for a connection, you could use netstat -a -p TCP | find "LISTENING". If you wanted to see connections to a particular port, e.g., 22, for Secure Shell (SSH) connections, you could use netstat -a | find ":ssh" , which would show the IP addresses of the remote systems connected via SSH, or netstat -a | find ":https" for HTTPS connections to web sites. If you wished to see host names rather than IP addresses, you could add the -f option, which displays a Fully Qualified Domain Name (FQDN) instead of an IP address for a remote system. E.g., netstat -a -f | find ":https". Since SSH, HTTP, and HTTPS use TCP rather than UDP transmissions, you don't need to add the -p parameter.

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Configuring PuTTY for X forwarding

The X Window System, aka X11 or simply X, provides a mechanism that allows you to have the graphical user interface (GUI) for an application running on a remote system to be displayed on the system on which you are running X server software. For systems running a Microsoft Windows operating system, you can use the free PuTTY program to establish a Secure Shell (SSH) connection to an SSH server and configure PuTTY to allow X forwarding so that you can run programs on the SSH server, but have their GUI displayed on the Microsoft Windows system on which you are running PuTTY.

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Location for PuTTY Tunnel Information

PuTTY stores information about sessions you have created to connect to a particular host in the Windows Registry at HKEY_CURRENT_USER\SOFTWARE\SimonTatham\PuTTY\Sessions. If you want to view the SSH tunnels configured for a particular host, i.e., the port forwarding settings for that host, you can navigate to HKEY_CURRENT_USER\SOFTWARE\SimonTatham\PuTTY\Sessions\SessionName\PortForwardings where SessionName is the name you have given to the session associated with the host. E.g., suppose you regularly establish an SSH connection to www.example.com and have named a session for that site MySite. You could navigate to HKEY_CURRENT_USER\SOFTWARE\SimonTatham\PuTTY\Sessions\MySite\PortForwardings to find the port forwardings settings. If you had named the session My Site, there would be a %20 in the session name stored in the registry as %20 is an HTML representation for the space character. You can doubleclick on the PortForwardings key in the right pane of the registry window to see the values stored in the key. You might see something like the following:

L22011=192.168.0.11:22,L33018=192.168.0.18:33018

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[/os/windows/network/ssh/putty] permanent link

OpenVPN

OpenVPN is free and open-source software that provides Virtual Private Network (VPN) connectivity that is available for a variety of operating systems. To use the software on a Microsoft Windows 10 system, download the the installer for Windows Vista and later from the OpenVPN Community Downloads page; get the OpenVPN community software not the PrivateTunnel software from the OpenVPN project - I mistakenly downloaded and installed PrivateTunnel when I first went to the OpenVPN site and then had to uninstall PrivateTunnel.

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Using the Windows Resource Monitor to monitor network activity

If you want to see the IP addresses to which a program on a Microsoft Windows system is establishing connections, you can use the Resource Monitor utility that is provided with Windows Vista and later versions of Windows to check on network connections from a particular application on the system. To start the program, you can click on the Windows Start button and type resmon or resmon.exe in the "Search programs and files" field on a Windows 7 system or the "Type here to search" field on a Windows 10 system. You should see the resmon utility returned as the best match.

When the Resource Monitor program is running, you can click on the Network tab and then TCP Connections to see network activity associated with programs currently running on the system . You can click on a column header, e.g. "Image" to sort the entries by the values in that column.

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Error occurred message when upgrading freeSSHd

I needed to upgrade freeSSHd, which is free Secure Shell (SSH) server software for Microsoft Windows systems, on a Windows 8 system. The software allows remote users to log into a command line interface on the Windows system via SSH and provides the capability to transfer files via the SSH File Transfer Protocol (SFTP). When I attempted to install the latest version of the software over a prior version, however, the installation was unsuccessful. If you see the following error message, you may need to stop the SSHD service prior to performing the upgrade:

An error occurred while trying to replace the existing file:
DeleteFile failed; code 5.
Access is denied.

Click Retry to try again, Ignore to skip this file (not recommended), or Abort to cancel installation.

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[/os/windows/network/ssh/freeSSHd] permanent link

Determining which program is listening on a port under Windows

If you want to know which application is listening on a particular network port on a Microsoft Windows system, e.g., port 80, the port used for HTTP connections to a web server, you can obtain that information from a command line interface (CLI) by obtaining a command prompt and using the netstat and tasklist commands which are provided with the operating system; you do not need to install any additional software, though there are programs that will allow you to view that information from a graphical user interface (GUI).

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Using SSH Keys with PuTTY

PuTTY is a free and open source network utility that allows you to establish Telnet and Secure Shell (SSH) connections to servers. It is commonly used on Microsoft Windows systms, but is also available for Linux and Apple OS X systems. You can use it for interactive SSH logins where you provide a userid and password to authenticate with an SSH server, but you can also use it for public key-based logins where the server has a public key that is matched against a private key stored on the system from which you are connecting. By a mathematical calculation based on large prime numbers, the public key and private key can be matched with one another as a means of authenticating the login.

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Determining if a Windows system supports the 5 GHz Wifi band

The Wi-Fi network adapter in a Microsoft Windows system may support dual band wireless connections, i.e, both the 2.4 GHz and 5 GHz bands for a wireless local area network (WLAN), or it may only only support the older 2.4 GHz standard. A radio frequency (RF) band is is a group of frequencies containing many channels. To determine if a wireless adapter can support both the 2.4 and 5 GhZ Wifi standards, you can obtain a command prompt and type the command netsh wlan show drivers. If you see 802.11a listed on the "Radio types supported line, then the adapter supports the 5 GHz as well as the 2.4 GHz bands.

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