985
edits
Changes
From SME Server
Jump to navigationJump to searchno edit summary
This is an introduction to using Public-Private Keys as applied to SSH. It has been written in response to questions regarding my CVS How-To.
This is an introduction to using Public-Private Keys as applied to SSH. It has been written in response to questions regarding my [http://www.wellsi.com/sme/cvs/cvs.html CVS How-To].
It currently covers the first three steps needed to use Public-Private keys
It currently covers the first three steps needed to use Public-Private keys
The following has been tested using a Mitel SME Server, and Windows XP& RedHat 8.0 clients.
The following has been tested using a Mitel SME Server, and Windows XP& RedHat 8.0 clients.
Some sections use PuTTY to connect to the server, it is a free implementation of SSH for Win32 platforms, with extensive online documentation. See Tom Carroll's HowTo for details of how to use PuTTY.
Some sections use [http://www.chiark.greenend.org.uk/~sgtatham/putty/ PuTTY] to connect to the server, it is a free implementation of SSH for Win32 platforms, with extensive [http://the.earth.li/~sgtatham/putty/latest/htmldoc/ online documentation]. See [http://www.carrollweb.net/putty/putty-howto.html Tom Carroll's HowTo] for details of how to use PuTTY.
Generate Public-Private Key Pairs
== Generate Public-Private Key Pairs ==
This section describes three ways to generate the public-private key pairs, and specifically a SSH protocol 2 RSA key pair.
This section describes three ways to generate the public-private key pairs, and specifically a SSH protocol 2 RSA key pair.
[[Image:Putty00.png]]
[[Image:Putty00.png]]
PuTTYgen can be used to generate the keys, which is described in detail in Chapter 8.2
[http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html PuTTYgen] can be used to generate the keys, which is described in detail in [http://the.earth.li/~sgtatham/putty/0.53b/htmldoc/Chapter8.html#8.2 Chapter 8.2]
1. Select SSH2 RSA.
1. Select SSH2 RSA.
2. Press Generate, and generate the key by moving the mouse.
2. Press '''Generate''', and generate the key by moving the mouse.
3. Change the Key comment field to something meaningful such as your name.
3. Change the '''Key comment''' field to something meaningful such as your name.
4. Enter a passphrase which is used to encrypt the key.
4. Enter a passphrase which is used to encrypt the key.
5. Save the public key.
5. Save the public key.
It is possible to use the SME Server itself to generate the public-private key pairs. This is done by using ssh-keygen.
It is possible to use the SME Server itself to generate the public-private key pairs. This is done by using [http://www.openbsd.org/cgi-bin/man.cgi?query=ssh-keygen ssh-keygen].
By default the pair is written to $HOME/.ssh/id_rsa and $HOME/.ssh/id_rsa.pub
By default the pair is written to $HOME/.ssh/id_rsa and $HOME/.ssh/id_rsa.pub
ssh-keygen -t rsa
Generating public/private rsa key pair.
Generating public/private rsa key pair.
Enter file in which to save the key (/home/e-smith/files/users/dummy/.ssh/id_rsa): [Enter to accept default]
Enter file in which to save the key (/home/e-smith/files/users/dummy/.ssh/id_rsa): ''[Enter to accept default]''
Created directory '/home/e-smith/files/users/dummy/.ssh'.
Created directory '/home/e-smith/files/users/dummy/.ssh'.
Enter passphrase (empty for no passphrase): [Your passphrase]
Enter passphrase (empty for no passphrase): ''[Your passphrase]''
Enter same passphrase again: [Your passphrase]
Enter same passphrase again: ''[Your passphrase]''
Your identification has been saved in /home/e-smith/files/users/dummy/.ssh/id_rsa.
Your identification has been saved in /home/e-smith/files/users/dummy/.ssh/id_rsa.
Your public key has been saved in /home/e-smith/files/users/dummy/.ssh/id_rsa.pub.
Your public key has been saved in /home/e-smith/files/users/dummy/.ssh/id_rsa.pub.
=== On RedHat 8.0 ===
=== On RedHat 8.0 ===
To generate the public-private key pair on a RedHat 8.0 box is identical to the SME Server, as both use OpenSSH.
To generate the public-private key pair on a RedHat 8.0 box is identical to the SME Server, as both use [http://www.openssh.com/ OpenSSH].
In this example I have specified the comment field.
In this example I have specified the '''comment field'''.
ssh-keygen -t rsa '''-C dummy@rh8'''
Generating public/private rsa key pair.
Generating public/private rsa key pair.
Your public key has been saved in /home/dummy/.ssh/id_rsa.pub.
Your public key has been saved in /home/dummy/.ssh/id_rsa.pub.
The key fingerprint is:
The key fingerprint is:
aa:bb:cc:dd:ee:ff:aa:bb:cc:dd:ee:ff:aa:bb:cc:dd dummy@rh8
aa:bb:cc:dd:ee:ff:aa:bb:cc:dd:ee:ff:aa:bb:cc:dd '''dummy@rh8'''
== Installing the Public Key onto the Server ==
== Installing the Public Key onto the Server ==
To make use of the Public-Private Key pair the Public keys must be put onto the server that will be accessed. The Public Key file and its contents do not need to be kept secret.
To make use of the Public-Private Key pair the Public keys must be put onto the server that will be accessed. The Public Key file and its contents do not need to be kept secret.
The Public Key needs to be saved in the file $HOME/.ssh/authorized_keys . For the user dummy on an SME Server it would be:
The Public Key needs to be saved in the file $HOME/.ssh/authorized_keys . For the user '''dummy''' on an SME Server it would be:
/home/e-smith/files/users/dummy/.ssh/authorized_keys
/home/e-smith/files/users/'''dummy'''/.ssh/authorized_keys
The directory .ssh should have permissions 700 and the file authorized_keys should have permissions either 644 or 600. If the directory does not exist it can be created as follows, which presumes that you are logged in as yourself, not root.
The directory .ssh should have permissions 700 and the file authorized_keys should have permissions either 644 or 600. If the directory does not exist it can be created as follows, which presumes that you are logged in as yourself, not root.
The authorized_keys file can store multiple public keys, one on each line, so the following examples always append to the end of the file.
The authorized_keys file can store multiple public keys, one on each line, so the following examples always append to the end of the file.
Public key from OpenSSH
=== Public key from OpenSSH ===
Copying the Public Key generated by ssh-keygen, $HOME/.ssh/id_rsa.pub
Copying the Public Key generated by ssh-keygen, $HOME/.ssh/id_rsa.pub
=== Public key from PuTTYgen ===
=== Public key from PuTTYgen ===
There are two main ways of doing this, they each require that the "Public key for pasting into authorized_keys file" is copied to the clipboard (see Step 7 on the figure above). For more details read the PuTTY manual.
There are two main ways of doing this, they each require that the "Public key for pasting into authorized_keys file" is copied to the clipboard (see Step 7 on the figure above). For more details read the [http://the.earth.li/~sgtatham/putty/0.53b/htmldoc/Chapter8.html#8.2 PuTTY manual].
One method is to paste the key into a file (putty.pub in the example below).
One method is to paste the key into a file ('''putty.pub''' in the example below).
Then copy this file into the $HOME/.ssh directory on the server. This file can then be appended to the authorized_keys file.
Then copy this file into the $HOME/.ssh directory on the server. This file can then be appended to the authorized_keys file.
cat putty.pub >> authorized_keys
cat '''putty.pub''' >> authorized_keys
The other method is simpler but more complicated to explain.
The other method is simpler but more complicated to explain.
Private Key files cannot be directly shared between PuTTY and OpenSSH, however PuTTYgen can convert the files.
Private Key files cannot be directly shared between PuTTY and OpenSSH, however PuTTYgen can convert the files.
1. Either press Load, or from the Conversions menu select Import Key.
=== Converting the OpenSSH Private Key to work with PuTTY ===
2. Change the Files of Type to All Files
1. Either press ''Load'', or from the ''Conversions'' menu select ''Import Key''.
2. Change the ''Files of Type'' to ''All Files''
3. Select the Private Key, id_rsa, that was created with ssh-keygen.
3. Select the Private Key, id_rsa, that was created with ssh-keygen.
4. Enter the passphrase to load the key.
4. Enter the passphrase to load the key.
5. The Key comment may be changed at this time.
5. The ''Key comment'' may be changed at this time.
6. Save the private key.
6. Save the private key.
Converting the PuTTY Private Key to work with OpenSSH
=== Converting the PuTTY Private Key to work with OpenSSH ===
1. Press Load and select the Private Key that was created with PuTTYgen.
1. Press ''Load'' and select the Private Key that was created with PuTTYgen.
2. Enter the passphrase to load the key.
2. Enter the passphrase to load the key.
3. From the Conversions menu select export OpenSSH key
3. From the ''Conversions'' menu select export OpenSSH key
4. Save the private key.
4. Save the private key.
Using public keys for SSH authentication
== Using public keys for SSH authentication ==
In these examples the server is the SME Server, and the clients will be Windows and RedHat 8.0
In these examples the server is the SME Server, and the clients will be Windows and RedHat 8.0
To start using PuTTY with SME Server see Tom Carroll's HowTo
=== In use with PuTTY ===
To start using PuTTY with SME Server see [http://www.carrollweb.net/putty/putty-howto.html Tom Carroll's HowTo]
To use the Private Key go to the PuTTY Configuration and select the Connection - SSH - Auth.
To use the Private Key go to the PuTTY Configuration and select the Connection - SSH - Auth.
Then in the Private key file for authentication: enter the path to the private key file, or find it using Browse.
Then in the ''Private key file for authentication'': enter the path to the private key file, or find it using ''Browse''.
When starting the PuTTY terminal the following is shown. You will need to enter the passphrase, if one was set.
When starting the PuTTY terminal the following is shown. You will need to enter the passphrase, if one was set.
Using username "dummy".
Using username "dummy".
Authenticating with public key "dummy@homepc" Using the private key generated on my windows machine
Authenticating with public key "dummy@homepc" '''Using the private key generated on my windows machine'''
Passphrase for key "dummy@homepc":
Passphrase for key "dummy@homepc":
Welcome to the Mitel Networks SME Server.
Welcome to the Mitel Networks SME Server.
Using username "dummy".
Using username "dummy".
Authenticating with public key "dummy@gatekeeper" Using the private key generated on my SME Server
Authenticating with public key "dummy@gatekeeper" '''Using the private key generated on my SME Server'''
Passphrase for key "dummy@gatekeeper":
Passphrase for key "dummy@gatekeeper":
Welcome to the Mitel Networks SME Server.
Welcome to the Mitel Networks SME Server.
In use with OpenSSH
=== In use with OpenSSH ===
This brief example shows the start of a SSH session where the username is specified using the -l option.
This brief example shows the start of a SSH session where the username is specified using the -l option.
ssh -l dummy gatekeeper
Enter passphrase for key '/home/dummy/.ssh/id_rsa':
Enter passphrase for key '/home/dummy/.ssh/id_rsa':
Last login: Tue Feb 18 11:38:43 2003 from somewhere
Last login: Tue Feb 18 11:38:43 2003 from somewhere
Welcome to the Mitel Networks SME Server.
Welcome to the Mitel Networks SME Server.
bash-2.05a$
bash-2.05a$
== Further Information ==
=== OpenSSH Files ===
OpenSSH Files
Files used by OpenSSH, full details can be found from the ssh-keygen (1) and sshd (8) manual pages.
Files used by [http://www.openssh.com/ OpenSSH], full details can be found from the [http://www.openbsd.org/cgi-bin/man.cgi?query=ssh-keygen ssh-keygen (1)] and [http://www.openbsd.org/cgi-bin/man.cgi?query=sshd sshd (8)] manual pages.
$HOME/.ssh/id_rsa
'''$HOME/.ssh/id_rsa'''
This is the private key, it contains the protocol version 2 RSA authentication identity of the user. This file should not be readable by anyone but the user.
This is the private key, it contains the protocol version 2 RSA authentication identity of the user. This file should not be readable by anyone but the user.
$HOME/.ssh/id_rsa.pub
'''$HOME/.ssh/id_rsa.pub'''
Contains the protocol version 2 RSA public key for authentication. The contents of this file should be added to the authorized_keys file on all machines where the user wishes to log in using public key authentication. There is no need to keep the contents of this file secret.
Contains the protocol version 2 RSA public key for authentication. The contents of this file should be added to the authorized_keys file on all machines where the user wishes to log in using public key authentication. There is no need to keep the contents of this file secret.
$HOME/.ssh/authorized_keys
'''$HOME/.ssh/authorized_keys'''
Lists the public keys that can be used to log into the user's account. This file must be readable by root. It is recommended that it not be accessible by others.
Lists the public keys that can be used to log into the user's account. This file must be readable by root. It is recommended that it not be accessible by others.
Each line of the file contains one key (empty lines and lines starting with a `#' are ignored as comments). Each protocol version 2 public key consists of: options, key-type, base64 encoded key, comment. The comment field is not used for anything (but may be convenient for the user to identify the key).
Each line of the file contains one key (empty lines and lines starting with a `#' are ignored as comments). Each protocol version 2 public key consists of: options, key-type, base64 encoded key, comment. The comment field is not used for anything (but may be convenient for the user to identify the key).
OpenSSH
=== Changing the passphrase ===
'''OpenSSH'''
You can change the passphrase at any time by using the -p option of ssh-keygen.
You can change the passphrase at any time by using the -p option of ssh-keygen.
