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According to some cygwin gods, the only official document that you should use is  which is probably valid, but it seems to aim at users with a fair bit of Linux/Unix knowledge.

The purpose of this tutorial is for Windows users who are perhaps less familiar with Unix commands wanting to try out the famous ssh server (openSSH) on a desktop Windows XP , Windows Vista or Windows 7 .

The behavior of Windows 2003 Server is different. Follow to install Cygwin SSH server on Windows 2003 Server.

There seems to be some problems when using cygwin ssh with McAfee 8.0i. A work around to that problem is available below.

Please don't send any questions to the cygwin mailing list to ask questions about this page as it seems to provoke them severely. They considered and declared the instructions on this page "broken" and "random" but won't constructively say what is "broken"; instead some went on launching personal attacks. The information here is provided "as is, in good faith" with no guarantee it will work. If it doesn't work, then it doesn't work.Don't send any questions to the Cygwin mailing list to ask why to provoke them. If you must go to Cygwin mailing list to ask, you better off before you go to the mailing list to ask questions and don't even mention that you have looked at this web page (to avoid provoking them off).

Read this .

Constructive comments are of course welcome, in the original spirit of the Internet, sharing experience and knowledge regarding bug fixes and improvements to benefit other users of the Internet community. My email address is

How to install a ssh server (called sshd, from ) on a Windows 2000 or XP

How to install a sftp server on a Windows 2000 or XP

The ssh server is an emulation of the UNIX environment and OpenSSH for Windows, by Redhat, called cygwin.

The file system on your target machine should be journalled (e.g. NTFS) because FAT file system has bugs in file access.

(1a) Login as Administrator

Windows XP - login as a user with Administrator privilege; Windows 2003 Server: login as local admin, it will not work for domain users or domain admin.

(1b) Make sure the current admin/user has a Windows password set.

If not, use Control Panel...User Accounts to create a password. Just to be on the safe side, after you created a password, logoff and then log in again.

(2a) Create a folder c:\cygwin

(2b) Download cygwin's setup.exe from and save setup.exe in c:\cygwin

Cygwin's setup.exe has some uncommon properties, to find out more.

(2c) For Windows 7 and Windows Vista, navigate to c:\cygwin in explorer,  right click the setup.exe icon, and select "Run as Administrator". Thanks to David Shanks for his contributions.

(2d) For Windows XP: Click Start...Run...and type c:\cygwin\setup.exe

If you are asked to select "Just Me" or "All Users", choose "All Users"

When it asks for "Local Package Directory", type c:\cygwin

Choose a download site that is "close" to you.

When a selection screen comes up (you can resize the windows to see better), click the little View button for "Full" view  , find the package "openssh", click on the word "skip" so that an appears in Column B, see (optional) find the package "tcp_wrappers", click on the word "skip" so that an appears in Column B, if you add "tcp_wrapper", you will most likely get "ssh-exchange-identification: Connectiion closed by remote host" error. If you get that error, edit the file  /etc/hosts.allow and add these two lines ALL: 127.0.0.1/32 : allow   ALL: [::1]/128: allow before the PARANOID line. (optional) find the package "diffutils", click on the word "skip" so that an appears in Column B,  find the package "zlib", click on the word "skip" (it should be already selected) so that an appears in Column B.

Notes:

tcp_wrappers provides host-based access control and possible need you to edit "/etc/hosts.allow"  zlib is the compression and decompression library that is used by many programs. Thanks to Lex Sheehan on the diffutils tips, and Thomas Braun for the hosts.allow tips.

Click to start installing cygwin and ssh.

Size of the basic cygwin system is more than 50 Meg.

(3) This paragraph is no longer valid for newer versions of Cygwin 1.7.2 and later.

REF:  http://www.cygwin.com/cygwin-ug-net/ov-new1.7.html

Right click My Computer, Properties, Advanced, Environment Variables See Click the "New" button to add a new entry to System variables: variable name is CYGWIN

variable value is ntsec tty

Note: by setting variable ntsec, it will break sshd on MinGW by generating the error "WARNING: UNPROTECTED PRIVATE KEY FILE".

Thanks to Peter Rust for this issue.

(4) Right click My Computer, Properties, Advanced, Environment Variables

See Select the Path variable and click the "Edit" button: append  ;c:\cygwin\bin to the end of the existing variable string.

(5)

For Windows 7 and Windows Vista you may need to do additional uninstall steps if previous attempts to install sshd fails.

on how to do clean uninstall.

For Windwos XP, you should login as a user with admin privilege and that user belongs to a Windows "Users" group.

For Windows XP , open a cygwin window by double clicking the icon; a black screen pops open,

For Windows Vista and Windows 7 , right click the icon and choose "run as administrator"; a black screen pops open, type

With recent releases of cygwin, there are some permission problems. Add these 6 commands as work around:

chmod +r  /etc/passwd

chmod u+w /etc/passwd chmod +r  /etc/group chmod u+w /etc/group chmod  755  /var   touch /var/log/sshd.log chmod 664 /var/log/sshd.log ssh-host-config    (manuall answer Yes to questions except) If the script says "This script plans to use cyg_server, Do you want to use a different name?"   Answer Yes, and type sshd_server as the user name. See Note 25 near the end of this web page if you need to run ssh-host-config again.

cyglsa-config

Thanks to David Spillett of Londdon, UK on the permission tips.

Thanks to Dave Lennert of Portland Oregon for the Windows 7 tips. Thanks to Frank Martin for the cyglsa-config tips.

When the script stops and asks you for "environment variable CYGWIN="  your answer is ntsec tty

( for an explanation of ntsec) ( for an explanation of tty ) (thanks to Peter Reutemann of New Zealand and Ron Dozier of University of Delaware) (thanks to Mike and Michael Pechner for the Windows Vista tip) (thanks to Kevin Hilton on the Vista tips in the ssh-host-config section)

reboot the computer.

Pop a cygwin window

Run "rebaseall" as desribed in

(6) While you are still in the (black) cygwin screen, start the sshd service, type

net start sshd or cygrunsrv  --start  sshd

on how to stop the sshd service.

If the service fails to start, try (thanks to Ross Beveridge of HP for this tip)

chown system /etc/ssh* chown system /var/empty  or chown sshd_server /var/empty net start sshd

If you get "ssh-exchange-identification: Connectiion closed by remote host" error.

edit the file  /etc/hosts.allow and add these two lines ALL: 127.0.0.1/32 : allow   ALL: [::1]/128: allow before the PARANOID line. Thanks to Thomas Braun for the hosts.allow tips.

(7) Make sure every Windows user has a password set, if not,  go to Control Panel....User Accounts and create a password.

(7a) Make sure every Windows user has done the following at least once:

Login in as the Windows user, pop a console command screen by clicking Start...Run....cmd

Thanks to Magno Corrêa of Brazil for the tip in (7a)

(8) Pop a cygwin window, harmonize Windows user information with cygwin, otherwise they cannot login

mkpasswd   -cl   >   /etc/passwd mkgroup   --local    >   /etc/group

If your XP logs on to a domain, you most likely have to manually edit /etc/group. .

If  your local account name is the same as the domain name, then you would need to use Windows's User admin function to

rename the loacal account from name to name.local Then rebuild the passwd and group files as shown above, then edit the /etc/group file as shown above. Open firewall's TCP port 22 (Thanks to Christopher Poda of Venturi Wireless, Sunnyvale, California)

If your XP logs on to a domain, you may want to edit /etc/passwd to replace /home/username by //unc_server/path_to_home 

(thanks to Geoff Thomas)

mkpasswd creates a password file from Windows' user list, for more details.

mkgroup creates a group file from Windows' user list, for more details. Thanks to John Skiggn of Cingular Wireless in Redmond, Washington for his tweak on domain user /etc/group

Test to see if sshd is working, pop a cygwin window (note: the command below is case sensitive) whoami

ssh    localhost

or ssh  -vvv  localhost or

ssh    "$USERNAME@127.0.0.1" if ssh complains "The authenticity of host xx.xx.xx.xx can't be established .... Are you sure you want to continue connecting (yes/no)?"  Answer yes (Thanks to Daniel Griscom of Suitable Systems)

If you get an error message like "ssh-exchange-identification: Connection closed by remote host",

it is probably caused by McAfee 8.0i, see . (Thanks to Ron Dozier of University of Delaware, USA)

Error is also related to /etc/hosts.allow file, see

If you get an error message like "entry point _getreent", or "QuerryService Status: Win32 error 1062", it is probably

caused by the existance of an older version of "cygwin1.dll" located in the search path. Do a full serarch of "cygwin1.dll" and remove the old version, except the current version at c:\cygwin\bin  (Thanks to Joe britton)

If you get a prompt without error messages, type

cd   /cygdrive/c ls if you see a directory listing, success! (type exit to end the cygwin ssh session)   Thanks to Roger Pack for his tips clarifying between Microsoft's ls.exe (installed by MS compilers) and cygwin's ls.exe

If you have a Windows username that contains space, expand the space into \ [space],

e.g. if the Windows login name is  Mickey mouse ssh  Mickey\  mouse@127.0.0.1

If you have a Unix system that does not know what to do with TERM cygwin, add to .login

If you have troubles ssh into the server, try run ssh-user-config

Thanks to Jared Kilgour for above $USERNAME variable substitution.

Thanks to Justin Kerk for the tip on quotes around $USERNAME to allow for spaces in username. Thanks to Ron Dozier of University of Delaware for the Unix .login tweak.

Windows XP SP2 and SP3:   open the Windows Firewall to allow TCP port 22 through Click Start...Control Panel....Security Centre....Manage Security Settings for Windows Firewall....Exceptions tab....Add Port... "Name of port" is ssh    "Port number" is 22 (check the "TCP" checkbox) (Thanks to Stefano of Sardegna, Italy for his Windows Firewall reminder)

If you don't have sufficient privileges to open port 22 above, possible due to a group policy or other reasons,

you can create an exception for SSHD. Click Start.. Control Panel...Security Center ... Windows Firewall...select the "Exception" tab. Click "Add Program" button  .. Browse to c:\cygwin\bin\sshd.exe (Thanks to Thomas Johnson for this work around)

If you previously used Windows XP SP1 and installed sshd service, then upgraded to Windows XP SP2,

The upgrade disables the sshd service and deletes the CYGWIN environment variable. Re-enter the environment variables and path. Click Start...Control Panel....Security Centre....Manage Security Settings for Windows Firewall....Exceptions tab....Add Port... "Name of port" is ssh    "Port number" is 22 (check the "TCP" checkbox) (Thanks to Chris Davitt of New Zealand   for this SP1 to SP2 problem)

Multiple Windows users Create other Windows users using the Control Panel...User Accounts. After you created (or removed) Windows users pop a cygwin windows to harmonize Windows user information with cygwin, otherwise they cannot login mkpasswd   --local   >   /etc/passwd mkgroup   --local    >   /etc/group Don't get too carry away with multiple users, if a user can successfully ssh into the box, he can "cd" to just about any directory.

Note:  The behaviors of Windows 2003 Server is different.

to install OpenSSH on Windows 2003 Server, by Stephen Pillinger of the School of Computer Science, University of Birmingham.

Users from the internal network (geeks call this a LAN) can

ssh  usersname@ip_address   (e.g. ssh   john@192.168.0.100)

On Unix/Linux systems, user names do not contains spaces. On Windows system, user names can have spaces.

If you have a Windows username that contains spaces, expand each space into \ [space], e.g. if the Windows username is  mickey mouse ssh  mickey\  mouse@192.168.0.100

If you have a NAT firewall, port forward (D-link calls this Virtual Server) TCP port 22 to the (internal) IP address

of the Windows box where the sshd server is running. See above diagram.

Users from the outside (geeks call this a WAN) can   (the IP address is your firewall/router's WAN address)

ssh  username@external_ip_address   (e.g. ssh   john@64.64.64.64 )

ssh  mickey\   mouse@external_ip_address  (e.g.  ssh  mickey\  mouse@64.64.64.64 )

Caveat Emptor :

-assuming you have an IP address that is accessible from the outside world; some ISP give non-accessible IP address (). to their customers. -assuming your ISP does not suffer from extreme paranoia, he/she allows "port 22 TCP" traffic through their network. -assuming your corporate firewall allows TCP port 22 and port forwards to the computer running the ssh server.

If your install includes tcp_wrapper and you get an error message like "ssh-exchange-identification: Connection closed by remote host", do

start ... run ... c:\cygwin\setup.exe , add "mc Midnight Commander" package (a friendly editor for those who are unfamiliar with Unix editors), Invoke cygwin cd /etc mc   highlight the file /etc/hosts.deny and edit (F4) change the line ALL:ALL EXCEPT localhost:DENY to ALL:ALL EXCEPT localhost AND '192.168.':DENY   (assuming your internal network is 192.168.xx.xx ) and edit the content of the file /etc/hosts.allow to be just one line. sshd: ALL (Thanks to Carl Falk of Sweden for the hosts.allow and hosts.deny content)

In some extreme cases,

if you want to use TCP port 443 as the sshd listening port  (instead of the default SSH port 22), . (Why? Port 443 is normally assigned to https traffic, even severely paranoia IT geeks will leave this port open. Some IT will even intercept TCP port 443 traffic and redirect them to a proxy server, in that case, you may want to try to use Putty as a ssh client and configure the Connections -> Proxy to connect via a friendly proxy server. )

  As a bonus, openssh includes sftp and sftp-server for doing encrypted file transfers.

These two programs function much like the familiar ftp-client and ftp-server.

For example, from a remote laptop, you can transfer (send and retrieve) files to your home computer (see above diagram).

sftp   username@ip_address (e.g.  sftp  john@32.97.166.74 ) sftp   username@hostname (e.g. sftp  john@supercomputer.ibm.com ) openSSH [which uses openSSL] has strong encryption capability. The encryption used by openSSH can be either AES-128, AES-192, AES-256, 3DES, Blowfish, cast-128, arcfour (RC4) The default encryption algorithm (cipher) is AES-128-CBC. You can (cipher) by adding a directive such as

Ciphers   blowfish-cbc,aes128-cbc,3des-cbc  to /etc/sshd_config for faster transfer. The sftp client I like best is .

Caveat Emptor :

-assuming you have an IP address that is accessible by the outside world, some ISP do not give out outside-accessible IP address. -assuming your ISP does not suffer from extreme paranoia, he/she allows "port 22 TCP" traffic through their network. -assuming your firewall allows TCP port 22 and port forwards to the computer running the ssh server.

After you establish a ssh or sftp connection into the Windows box,

changing directory is rather painful, for example, to change to "my documents", type cd    "/cygdrive/c/documents and settings/$USERNAME/my documents"

Similarly, to change directory to d: drive

cd    /cygdrive/d

To reduce pain, use a graphical sftp client such as .

Where can you find a ssh or sftp client ?

(1) is the best ssh client for Windows, it also has psftp.exe which is a console mode sftp client. (2) Commercial software vendors such as Software. (3) , a free, GNU (GPL) licensed sftp client.

If you prefer to use a graphical client to do sftp file transfers,

purchase a high quality commercial software called from VanDyke Software in Albuquerque, New Mexico, USA or use , a free, GNU (GPL) licensed sftp client, or use , a free, GNU (GPL) licensed sftp and scp client. Also, ftp.ssh.com in their directory, there is a Windows version of ssh and sftp client for non-commercial use, thanks to Stephan of Rutgers State University of New Jersey for the link.

Once you have a sshd working and you can ssh into the machine (from LAN or WAN), there are many things you can do with it. For example, (now absorbed by Microsoft ) has many console mode utilities you can use. Other very, very useful things you can do with ssh is to tunnel tcp applications under the ssh protocol, giving them a strong cryptographic protection while traveling over the insecure public network.

openSSH [which uses openSSL] has strong encryption capability.

The encryption used by openSSH can be either AES-128, AES-192, AES-256, 3DES, Blowfish, cast-128, arcfour (RC4) The default encryption algorithm (cipher) is AES-128-CBC. You can (cipher) by adding a line such as

Ciphers   blowfish-cbc,aes128-cbc,3des-cbc  to /etc/sshd_config (Blowfish runs faster than AES-128)

Below are some popular plain-text, pure TCP protocols that are unfortunately still in common use today.

Fortunately these protocols can benefit from the protection of a ssh tunnel:

POP3 (tcp port 110)  IMAP (tcp port 143)  SMTP (tcp port 25)  TELNET (tcp port 21)  VNC (tcp port 5900) Print server traffic (typically tcp port 9100) Windows Share, or Samba Share, SMB protocol (tcp port  445)

Note:

The world is moving away (rather slowly) from plain text protocols by hardening them with TLS or SSL: newer versions of POP3 servers have TLS support at port 110; and SSL support at port 995 newer versions of IMAP servers have TLS support at port 143; and SSL support at port 993 newer versions of SMTP servers have TLS support at port 25 A version of "smtps" uses port 465 with SSL support, now it becomes legacy (depreciated). SMTP can also use port 587 in plain text or TLS. newer versions of telnet servers have SSL support at port 992

See.

See See at your home office or main office. See traffic under ssh.

Sometimes, there are applications such as midnight back-up of files to a data centre Linux server using "rsync encrypted with ssh", 

you want to be able to ssh from one machine to another machine (without a person sitting at a console to type the password). on how to ssh from one machine into another machine without typing a password, i.e, how to use public key authentication.

Once you can ssh from one machine to another machine without typing a password, your task of doing rsync over ssh

is practically 90% done. Furthermore, creating a batch file and invoke the batch file using Control Panel's "Schedule Tasks" (Task Scheduler) will do "secure backup" automatically to a remote server. In Linux world, add a cron job to invoke "rsync -e ssh"

How to install a ssh client (called ssh)

for a tutorial on how to setup a ssh client on Windows 2000 or Windows XP

How to install a smtp server [exim] on a Windows machine

for a tutorial on how to setup exim, a mail transfer agent on Windows 2000 or Windows XP as a learning exercise.

Note 25: if you run ssh-host-config when sshd is installed, ssh-host-config will not ask for the CYGWIN value.

In that case,  stop and remove the sshd service, then run the ssh-host-config script again, see below.

cygrunsrv  --stop  sshd

cygrunsrv  --remove sshd

ssh-host-config

cygrunsrv  --start sshd

Go to Control Panel, Classic View, Administrative Tools, Computer Management,

or click Start...Run...compmgmt.msc

delete the sshd user account.

Thanks to Dave Abrahams of Boost Consulting for the sshd user account deletion hint.

Reference:

by ITeF!x is another implementation of cygwin-openssh server for Windows.

Thanks to Mike Skallas for his tips on "privilege separation" during the setup script.

Thanks to Jan Haul of Hamburg, Germany for his WinSCP link. Thanks to Brad Erdman, Institute for Advanced Computer Studies, University of Maryland, USA for his confirmation of cygwin-sshd working on Windows Server 2003 Thanks to Richard Goodman of UK for his tips on the order of CYGWIN variable.

© 2003-2012 Nicholas Fong

Last revised: June 26, 2012