HOW TO Set Up an SSH Server in Windows 7/10

HOWTO-setup-SSH-in-Win7-10.txt

SSH on Windows 7 ("The full awesome implementation")
===============================================================================

http://codeoptimism.net/2010/10/08/SSH-on-Windows-7-the-full-awesome-implementation
http://codeoptimism.net/2010/10/13/SSH-on-Windows-7-continued-charade-ssh-rsync-Unison

22 Dec 2019 Update: Corrected paths for PuTTY; Clarifications for some steps;
11 Dec 2017 Update: Added full paths for Task Manager 'Action' items; 
15 Aug 2016 Update: Added .bashrc alias for 'ping'; 
15 Feb 2016 Update: Added 'ssh-pageant' to Step 1 as Cygwin package to install; 
05 Apr 2015 Update: New 'ssh-host-config' mode; Fixed a few typos; Tweaks for 
                    installing as an unprivileged user; 
25 May 2014 Update: Fixups for installing 'Cygwin64' & installing on 32-bit Win; 
                    Cleaned up all procedures; Enhanced client keygen section; 
09 Mar 2014 Update: Made notations for installing 'Cygwin64'; 
30 Sep 2013 Update: Replace 'charade' w/ 'ssh-pageant'; 
30 Jan 2012 Update for added clarity & more options; 
02 Sep 2011 Update for clarity & Win XP/7 differences; 
16 May 2011 Updated and polished; 
08 Oct 2010, 13 Oct 2010 Original; 


Configuring Secure Shell on Windows 7 requires a special configuration...

Note that you can do both the server & client procedures on the same machine, 
allowing your machine to act as both (usually the most useful configuration).


---------------------------------------------


SSH Server Installation & Configuration

1. Install 'Cygwin'.  Be sure to include editors ('vi'/'vim' and/or 'emacs'), 
   'openssh', all the crypto packages, packages 'rsync' and 'unison', and the 
   package 'ssh-pageant'.  (Suggested Unison version is 2.40.102.)

   Note that you can install from the Internet (http://www.Cygwin.com), or from 
   the repository included with these instructions.  (The included repository is 
   small, containing just enough packages to make the SSH applications work.)

   Note that when installing the 64-bit version of Cygwin, it will default its 
   installation directory to 'C:\Cygwin64\'.  You likely want to change this 
   to 'C:\Cygwin\'; these instructions assume this is the case.

   Note that when installing 32-bit apps on 64-bit Windows, installation folders 
   go in 'C:\Program Files (x86)\' while on 32-bit Windows, the only apps folder 
   that exists is 'C:\Program Files\'.  The following instructions assume you 
   are installing on a 64-bit system; use whatever is appropriate for your case.

   Note that Cygwin installation may return a dialog after installation saying 
   that the program may not have installed correctly.  You can likely disregard 
   this; it appears to be incorrect/unnecessary.

2. Configure the Cygwin bash shell to run as 'Administrator'.  

   In the Start menu, right-click the 'Cygwin' icon, then select 'Run as 
   administrator'.

3. Open Cygwin and run 'ssh-host-config' to generate a set of OpenSSH RSA keys 
   (do this even if you already have a set of keys you wish to install instead 
   later).  (Note, depending on the version of Cygwin installed, you may not get 
   all these questions; adjust accordingly.)

   Answer 'Yes' to using strict mode.
   Answer 'Yes' to privilege separation.
   Answer 'Yes' to creating a new local account.
   Answer 'No' to installing as a service. (Critical!  Explanation follows.)

4. Immediately after, enter the following (be sure to include the '>' symbol):

     mkdir .ssh
     > ~/.ssh/authorized_keys

    Creating this file from the terminal assigns the appropriate permissions. 
    (Cygwin's 'None' account is granted read access.)

5. If you wish to only use PKI cryptography to log in, edit '/etc/sshd_config':

   Copy/paste the line containing 'PasswordAuthentication', then uncomment the 
   copy & change the setting to 'No'.

6. Close ('exit') Cygwin.


Server Environment Variables Configuration

This will allow us to store certain standalone executables, and omit their full 
path when launching them.  It will also allow launching the server from outside 
of a Cygwin bash shell. (Note that Cygwin's 'bin' directories will appropriately 
take precedence, as seen in the file 'C:\Cygwin\etc\profile'.)

1. Create the folder 'C:\Program Files (x86)\PuTTY', which should be created on 
   installing PuTTY; You may want to install PuTTY at this point... Be sure to 
   install the 32-bit version, since you will later add Kitty, which is 32-bit.

2. Open the Control Panel (press '<WindowsKey>+<Pause/Break>'), then click (on 
   the left sidebar) 'Advanced system settings' to open the 'System Properties' 
   dialog.

3. Click the 'Environment Variables' button; under 'System variables', double-
   click the 'Path' variable. (Or single-click and click the 'Edit..' button.)

4. Add the following to the end of the 'Variable value' string, being careful to 
   include the leading semicolon:

        ;C:\Program Files (x86)\PuTTY;C:\Cygwin\bin

   (You may prefer to put 'C:\Program Files (x86)\PuTTY' part in the 'User PATH' 
   instead, which is fine.) 

5. Click OK, closing the dialogs.


Launching the SSH Daemon on the Server

1. Copy 'hstart.exe' to 'C:\Program Files (x86)\PuTTY'.  (This is in the 
   'put-in-c-progfiles-putty' folder; you can copy all the files in this folder
   to 'C:\Program Files (x86)\PuTTY' at this point, if you wish.

   Note: 'hstart' will help to hide a console window, but it's also very useful 
   for de-elevating application launches, as you'll see later. 
   (See http://www.ntwind.com/software/utilities/hstart.html for more info.)

2. Open 'Task Scheduler' on the server using "Run as Administrator".  (Why use 
   'Task Scheduler'?  To bypass the permissions elevation prompt when the apps 
   start up.)  You'll find 'Task Scheduler' in the Start Menu, under 'All 
   Programs' / 'Accessories' / 'System Tools'.  

3. Click 'Task Scheduler Library' (left sidebar), then click 'Create Task..', 
   located under 'Actions' on the right sidebar. (You may need to enlarge the 
   window a bit to see everything.)

4. Under the 'General' tab, name the task 'SSHD', optionally set the Description 
   to "Start the SSH daemon", and check 'Run with highest privileges'.  If you 
   plan to launch the server daemon when the system starts up, then also check 
   'Run whether user is logged on or not'.

5. Under 'Triggers', click 'New..' & set it to launch when you (or anyone) logs 
   on. (You can also set it to launch when the machine boots up, which is less 
   secure but can be more useful, in which case you will want to have 'Run 
   whether user is logged on or not' checked on the 'General' tab.)

6. Under 'Conditions', uncheck 'Start the task only if the computer is on AC 
   power' if the server is not a laptop (or if you don't care about power use 
   issues).

7. Under 'Actions', click 'New..' and accept the default action of 'Start a 
   program' and enter:

     Program/script:  "C:\Program Files (x86)\PuTTY\hstart.exe"
     Add arguments:   /noconsole "C:\Cygwin\usr\sbin\sshd.exe -D"
     Start in:        [leave blank]

8. Click 'OK' (more than once) to confirm all & close the 'Create task' dialog, 
   then press <F5> on the Task Manager window to refresh, and then Run the SSH 
   daemon by right-clicking the item and selecting 'Run'.  (Press <F5> again to 
   refresh & verify that it's running.)

9. Keep the Task Manager open if you're also installing the SSH client apps on 
   this machine; otherwise close it.

Q: Why did we go to all this trouble instead of allowing 'ssh-host-config' to 
   install 'SSHD' as a service?

A: We want the daemon to run as a child process of 'Explorer.exe'. Although you 
   can 'allow a service to interact with the desktop', it won't have the desired 
   effect.  This way we can launch e.g., 'notepad' remotely and have it open in 
   our user session on the server, as a child of 'Explorer', fully visible and 
   ready for input.

---------------------------------------------


Client Public-Key Encryption Configuration

1. Install PuTTY on the client machine (you can install the version located in 
   the 'install-in-windows' folder) and follow the installer's prompts (the 
   defaults are all good to use).

2. Launch 'PuTTYGen' (from the Start menu, in the 'PuTTY' folder), regardless of 
   whether you need to make a new set of keys or will import an existing set.

3. If you need to generate a new set of RSA keys ('SSH-2 RSA' type), select a 
   bit size (1024 or 2048, larger is better), then click 'Generate' and follow 
   the prompts (otherwise skip to the next step).

   1024 bit keys are useful for using SSH from a slow smartphone (or one with a 
   low signal), as it will negotiate a connection quicker.  However, it's more 
   preferred to use 2048 bits for better security.

4. If you already have a set of RSA keys you wish to use, import them from the 
   menu 'Conversions' / 'Import Key'.

5. Comment the key to identify it (edit the suggestion in 'Key comment').  One 
   suggestion: 'User@Server-PC_Date', e.g. 'Chris@MyMachine_2014-0525'.  This 
   comment shows up at the end of the key line in the server's 'authorized_keys' 
   file, allowing you to easily determine the machine from which it originated.

6. Absolutely give it a passphrase!  (Enter one in 'Key passphrase' and again in 
   'Confirm passphrase'.)  This will encrypt the private key (which is why we'll 
   install 'Pageant' later; it will provide a single logon request to decrypt 
   your key for use during each session).

7. Click 'Save private key' to save the PuTTY private key to your hard drive.  
   Suggested location to save it: Since you'll be saving your OpenSSH version of 
   the keys in 'C:\Cygwin\home\[user]\.ssh\', put all your keys there.

   For a key name, you could use something like 'User@Server-PC.ppk'. However, 
   if you are in a mixed-platform environment, you'll likely be better off 
   following OpenSSH standards.  In this case, your keys would be named: 

     id_rsa.ppk = PuTTY private key
     id_rsa.pbk = PuTTY public key
     id_rsa     = OpenSSH private key
     id_rsa.pub = OpenSSH public key

   If you need to deal with multiple sets of keys, you might prepend these names 
   with the name of the owner or platform, e.g., 'chris.id_rsa.ppk', or 
   'mypc.id_rsa.ppk' for example.

   However you decide, be consistent in naming all four of the key files you're 
   creating.

8. Click 'Save public key' to save the PuTTY public key (naming it, as in our 
   last example, 'id_rsa.pbk') and save it in the same location.

9. In the 'Conversions' menu, select 'Export OpenSSH key' & save the equivalent 
   OpenSSH private key as 'id_rsa'.  (Note: this file has no extension.)  You'll 
   want this key later for Cygwin to use (or to copy to a Linux or OSX account); 
   the standard format for private keys is different from what PuTTY uses.  Save 
   this key as 'C:\Cygwin\home\[user]\.ssh\id_rsa'.

10. If you're using the client machine as an SSH server as well, then you'll 
   already have an 'authorized_keys' file in 'C:\Cygwin\home\[user]\.ssh\'; if 
   not, then create one now (using the procedure in the 'server' section above 
   to ensure the file has the desired ownership/premissions).  Do this even if 
   you think you "don't need it" (it won't hurt anything by being present in 
   any case).

11. Swipe and copy the public key displayed at the top of the 'PuTTYGen' window 
   and paste it at the end of your 'authorized_keys' file & save it.  This key 
   is your corresponding OpenSSH public key.  If/when you decide to use this 
   machine as an SSH server, you'll want the server to recognize your keys as 
   valid (i.e., you'll want to authorize yourself).

12. If your OpenSSH public key is the only key in the 'authorized_keys' file, 
   then you can copy the 'authorized_keys' file and paste it as 'id_rsa.pub', 
   your OpenSSH public key file.  Otherwise, create 'id_rsa.pub' as a new file, 
   and paste your OpenSSH public key into this file & save it.

13. You can close the 'PuTTYGen' window at this point.

14. Finally, copy the contents of the 'id_rsa.pub' file (located on the client) 
   into the 'authorized_keys' file (on the server).  For a Windows server, this 
   file is 'C:\Cygwin\home\[user]\.ssh\authorized_keys'.  For a Linux server, 
   this file is 'home/[user]/.ssh/authorized_keys'.  A secure Remote Desktop 
   connection works fine for this, or you can use WinSCP, or just use a thumb 
   drive.  Note that the public key file is not confidential; it's 'public'.  
   (By the same token, NEVER email an unencrypted private key -- under ANY 
   circumstances!)


Client Applications - Installation & Configuration

1. On the client system, create the folder 'C:\Program Files (x86)\PuTTY'.  
   (Better yet, just install PuTTY, which will create this folder for you, and 
   handle some of the other items below.)

2. Download 'KiTTY.exe' to 'C:\Program Files (x86)\PuTTY' (or use the version 
   in 'put-in-c-progfiles-putty').  Note that 'KiTTY' is a 32-bit Windows-only 
   fork of PuTTY whose additional features have considerable advantages.

3. Rename 'putty.exe' to 'putty-orig.exe' (as needed), then copy 'kitty.exe' and 
   paste it & rename it to 'putty.exe'; this is needed for compatibility with 
   PuTTY's 'Pageant' application.

4. Create or download 'kitty.ini' to 'C:\Program Files (x86)\PuTTY', and give it 
   the following entries:

     [PuTTY]
     keys=load

   This will copy KiTTY's configuration to PuTTY's registry keys on each exit, 
   maintaining compatibility with tools such as 'Plink' and 'Pageant'.

5. The above won't work if the 'HKEY_CURRENT_USER\Software\SimonTatham\PuTTY' 
   registry key doesn't exist.  Assuming you haven't installed PuTTY, the fast 
   solution is to 'merge' a '.reg' file to create the needed entry.

   You can do this by right-clicking the '.reg' file and selecting 'Merge' (or 
   by opening 'regedit.exe' and under 'File' selecting 'Import..', then finding 
   the '.reg' file, which does the same thing).

6. Download 'Pageant.exe' to 'C:\Program Files (x86)\PuTTY' (or copy the version 
   in 'put-in-c-progfiles-putty').

7. Open 'Task Scheduler' on the client.  You'll find it in the Start Menu, under 
   'All Programs' / 'Accessories' / 'System Tools'.

8. Click 'Task Scheduler Library' (left sidebar), then click 'Create Task..', 
   located under 'Actions' on the right sidebar. (You may need to enlarge the 
   window a bit to see everything.)

9. On the 'General' tab, name the task 'Pageant', optionally add a Description 
   "Start Pageant, the PuTTY equivalent of 'ssh-agent'", and be sure NOT to 
   check 'Run with highest privileges'.

10. Under 'Triggers', click 'New..' & set it to launch when YOU log on (i.e., 
   not 'for any user' -- for YOU, specifically).

11. Under 'Conditions', uncheck 'Start the task only if the computer is on AC 
   power' if the server is not a laptop (or if you don't care about power use 
   issues).

12. Under 'Actions', click 'New..' and enter (assuming the canonical key name):

     Program/script:  "C:\Program Files (x86)\PuTTY\Pageant.exe"
     Add arguments:   C:\Cygwin\home\[user]\.ssh\id_rsa.ppk
     Start in:        [leave blank]

13. Click 'OK' (more than once) to confirm all & close the 'Create task' dialog, 
   then press <F5> on the Task Manager window to refresh, and then Run the 
   Pageant app by right-clicking the item and selecting 'Run'.  (Press <F5> 
   again to refresh & verify that it's running.)

14. Type in your passphrase when prompted by Pageant.  You should see either a 
   dialog box (which might not be on top), or an icon in the task bar... 

   Note that you may need to edit the system tray properties so that the icon 
   will be displayed in the system tray.  To do this, right-click the task bar 
   and select 'Properties'; under the 'Taskbar' tab, click "Customize..."; find 
   "PuTTY SSH authentication agent", pull down the corresponding 'Behaviors' 
   control, and select "Show icon and notifications".  Click "OK", then close 
   the 'Taskbar and Start Menu Properties' dialog box.

15. Close the Task Scheduler.


Running 'Pageant' & 'KiTTY' to Create an SSH Session

1. You should see 'Pageant' in the System Tray notification area.  Right-click 
   on it and select 'New Session'.  (If you don't see this, double-check the 
   above steps; you may need to enable 'Show icons and notifications' in the 
   system tray options.)

2. 'Pageant' should open 'KiTTY' (not 'PuTTY').  Add the server's hostname (or
   IP number) where indicated at the top of the 'Session' page.  (If you want 
   to use hostnames instead of IP numbers, you should install a custom 'hosts' 
   file in 'C:\Windows\system32\drivers\etc\'.)

3. Under 'Connection' / 'Data', in the 'Auto-login username' textbox, enter the 
   username for your account on the server host.

4. Under 'Connection' / 'SSH' / 'Auth', click "Browse" and surf to your PuTTY 
   private key ('.ppk'), which should be in 'C:\Cygwin\home\[user]\.ssh'.

5. Back under 'Session', in the 'Saved Sessions / New Folder' textbox, type in a 
   session name of your choice (for example, 'User@ServerHost') & click 'Save'.

6. Click 'Open' to connect to the server...

Now, whenever you boot & log into the client machine, Pageant will prompt for 
your passphrase to access your PPK private key (and it will remember it until 
you log out).  After that, you can launch SSH sessions using Pageant's list of 
'Saved Sessions' by right-clicking the Pageant icon in the systray notification 
area, and Pageant will automate key verification for you.  (This is the Windows 
version of 'ssh-agent' operation in OpenSSH.)


File browsing on the Server from the Client

Now install 'WinSCP' (wherever it wishes); you will likely need to install using 
"Run as Administrator".  Configure nothing.  With 'KiTTY' fully connected to the 
server, click its top-left icon (in its title bar).  Select 'Start WinSCP' (near 
the bottom of the list).  

There you are: Full SFTP access without even configuring WinSCP!  (If it failed 
to connect, you may have already had WinSCP installed; try re-installing it, 
opting to delete configuration files; this is one solution.)


Launching applications on the Server from the Client

As our SSH daemon runs with administrative privileges on the server machine, we 
have full remote system access, which can be a security concern.  Often, we will 
want to launch an application on the server with non-elevated privileges.  To do 
this, you can use the command 'hstart.exe /nonelevated'.  

An even more convenient way to do this is to create an alias in your '.bashrc' 
file on the server, which is located in 'C:\Cygwin\home\[User]\.bashrc'.

Consider adding the following to '.bashrc' (where 'noel' stands for 'No Elevated 
Privileges'):

    alias noel='hstart.exe /nonelevated '
    alias ping='$SYSTEMROOT/System32/ping.exe '

You'll want to then reload the '.bashrc' file using the command '. ~/.bashrc'.  

Now you can launch an application using a shell command, e.g., 'noel notepad', 
entered on the client, and the app will run on the server with a 'Medium' (i.e., 
non-elevated) authorization level, just as a standard program would. 


Configuring Cygwin to Support SSH Sessions

In the above, we established an SSH session with 'KiTTY'.  However, to take full 
advantage of Cygwin and SSH, it's equally important that your Windows client can 
connect with Cygwin's SSH (or SSH on a Linux or Mac machine).

As Pageant handles authentication for KiTTY, so 'ssh-agent' authenticates you 
for 'ssh.exe' in Cygwin & Linux.  (For more information on this subject, refer 
to http://www.ibm.com/developerworks/library/l-keyc2/#1.)

However, we're on Windows!  We like KiTTY, and Pageant has a nice interface, so 
it should be all we need.  There's a solution: 'ssh-pageant' is an ssh-agent for 
Cygwin that proxies requests to Pageant.  It's a Windows-centric variation on 
'keychain' (http://www.ibm.com/developerworks/library/l-keyc2/#2 for more info).

The latest versions of Cygwin now have 'ssh-pageant' available.  However, if you 
need to get 'ssh-pageant', surf to https://github.com/cuviper/ssh-pageant, or 
you can install the appropriate version located in the 'put-in-c-Cygwin-bin' 
folder.   (The alternative in the original version of this procedure, 'charade', 
has known permissions issues, so the preferred agent is 'ssh-pageant' now.)

On the client,

1. Install 'Cygwin' and 'hstart' and configure the environment variables on the 
   client as was done previously on the server.

2. Download the approriate pre-built binary for 'ssh-pageant' (or use the 
   version in 'put-in-c-Cygwin-bin', or just have Cygwin install it).

3. If hand-installed, copy 'ssh-pageant.exe' to 'C:\Cygwin\bin\' and make sure 
   it's executable, then copy its man page, 'ssh-pageant.1', to 
   'C:\Cygwin\usr\share\man\man1\'.  

4. Edit 'C:\Cygwin\home\[User]\.bash_profile' (or '.bashrc') and add the lines

     # ssh-pageant
     eval $( /usr/bin/ssh-pageant -ra /tmp/.ssh-pageant )

   anywhere in the file.  (Note that in Linux, the SSH agent will be launched 
   automatically by Gnome; in Cygwin, we need to launch it explicitly.)

5. Run the Pageant task, launch a local Cygwin shell, & connect to your server: 
   'ssh [user]@[hostname]' (or 'ssh [hostname]' if the account names match).  
   You should be able to connect without a password challenge. 

Now, with 'ssh-pageant' operational, we can use tools like 'rsync' and 'unison' 
through SSH connections.

Remember when we exported our private key in OpenSSH format (to 'id_rsa')?  
That's the file that 'ssh.exe' requires.


Using 'unison' to Sync Files Between Hosts

Refer to the 'HOWTO-unison-install-in-win7.txt' file in the 'unison' folder for 
details on how to install and configure Unison.  Sans the above, Unison is the 
only cross-platform file sync'ing tool available currently.


Using 'rsync' to Copy Files Between Hosts

With the above setup in place, we can sync files in cross-platform fashion using 
the Linux tool 'rsync' that's provided in Cygwin.  Here's an example bash script 
used to push files over the network using 'rsync' that can handle spaces in file 
names:

---------------------------------------------
#!/bin/bash
receiver=$1

# escape spaces in file paths
# (the escapes won't be visible if you echo... you'd need to triple escape... 
# which we don't want)
src=`cygpath $2`
src="echo $src | sed 's/ /\\ /g'"
src=`eval $src`

if [ $# = 2 ]
then
	dest=$src
	#src=$src/
else
	dest=`cygpath $3`
	dest="echo $dest | sed 's/ /\\ /g'"
	dest=`eval $dest`
fi

source ~/.ssh-agent

# rsync
# -a, archival mode, does:
#	-r (recursive)
#	-l (copy symlinks as symlinks)
#	-p (preserive permissions)
#	-t (preserve modification times)
#	-g (preserve group)
#	-o (preserve owner)
#	-D (preserve device & special files)
# -v, verbose
# --delete, delete extraneous files from destination dirs (DANGEROUS)
# --rsh, the remote shell to use
# -z, compress file data during the transfer

# ssh
# -a, disables agent forwarding
# -x, disables x11 forwarding
# -c, set the cipher specification (blowfish being the quickest)

#LAN rsync:
rsync -s -av --delete --rsh="ssh -ax -c blowfish" "$src" $receiver:"$dest"
#WAN rsync:
#rsync -s -avz --delete --rsh="ssh -ax" "$src" $receiver:"$dest"
---------------------------------------------

I call the script from within my text editor like this: 

  cmd /c bash ~/push.sh Chris-Laptop 'C:\abc\some_source_dir' 'C:\some_dest_dir'

or

  cmd /c bash ~/push.sh Chris-Laptop 'C:\abc\source_dir\' 'C:\abc\dest_dir\'

or just 

  cmd /c bash ~/push.sh Chris-Laptop 'C:\abc\source_dest\' 

if the path is equivalent at the destination.

Note: It's rather important to understand the distinction of a trailing slash 
on the source folder when using 'rsync' (especially with '--delete' option). 

Back up your data before experimenting!

====================================================================================