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--- other:putty_conf [2022/08/03 12:44]
jypeter [Starting a session from a desktop shortcut]
+++ other:putty_conf [2023/03/15 15:15]
jypeter [Using ssh keys] Added warning about files' extensions
@@ Line 1: / Line 1: @@
 ====== Configuring and using PuTTY/Pageant ======
-PuTTY is a free and easy to use [[other:ssh|ssh client]] for **Windows**. You can use it to connect to your favorite remote Linux servers in text mode, and start remote graphical applications if you also have a running [[other:win10wsl#installing_an_x_server|X server]]
+PuTTY is a free and easy to use [[other:ssh|ssh client]] for **Windows**. You can use it to connect to your favorite remote Linux servers in text mode, and start remote graphical applications if you also have a running [[other:x_conf|X server]]
 ===== Installation =====
@@ Line 54: / Line 54: @@
     * Specify your login name (on the LSCE servers) in **Auto-login username**. This way you won't have to type it when you connect to the Linux server!\\ {{ :other:putty_06.png?direct |}}
   * In the ''Connection'' => ''SSH'' => ''Kex'' category:
-    * **<wrap hi>Unselect Attempt GSAPPI key exchange</wrap>**!\\ If you forget to do this, connecting to a server will seem to take forever (if it works at all)...\\ {{ :other:putty_gssapi.png?direct |}}
+    * **<wrap hi>Unselect Attempt GSSAPI key exchange</wrap>**!\\ If you forget to do this, connecting to a server will seem to take forever (if it works at all)...\\ {{ :other:putty_gssapi.png?direct |}}
   * In the ''Connection'' => ''SSH'' => ''Auth'' category:
     * Select **Allow agent forwarding**. This is the same as [[/other:ssh#standard_usage|using ssh with the -A option]]\\ {{ :other:putty_07.png?direct |}}
   * In the ''Connection'' => ''SSH'' => ''X11'' category:
-    * Select **Enable X11 forwarding**. This is the same as [[/other:ssh#standard_usage|using ssh with the -X option]]\\ {{ :other:putty_08.png?direct |}}
+    * Select **Enable X11 forwarding**. This is the same as [[/other:ssh#standard_usage|using ssh with the -X option]]\\ Note: remember that you will also need an [[other:x_conf|X server running]] in order to display graphics!\\ {{ :other:putty_08.png?direct |}}
   * When you have finished updating the settings, **do not forget to go back to ''Category'' => ''Session'' and Save the session**!\\ {{ :other:putty_09.png?direct |}}
@@ Line 115: / Line 115: @@
   * You can now connect to the remote server just by clicking on the desktop shortcut, instead of right-clicking on the ''Pageant'' icon!
-===== Using ssh keys =====
+===== Using ssh keys with PuTTY/Pageant =====
+<WRAP center round alert 60%>
+In this section, we will use files that have the same base name, and different extensions.
+You should **make sure that you can [[other:win10config#displaying_hidden_folders_and_files_and_the_files_extension|see hidden folders, and files' extensions]]** before you go further!
+</WRAP>
 Read the [[other:ssh#using_ssh_keys|Using ssh keys]] section if you don't know what //ssh keys// are
-==== Existing ssh keys ====
+<WRAP center round important 80%>
+  * **Do not lose** the (existing) ssh keys files you have, or the keys that you will create
+    * It is recommended to **keep a copy of these files** on another computer!
+  * **Do not forget** the passphrase that will be used to unlock the private key
+    * If you save the passphrase in a file, **do not** put this file in the same place as the ssh keys
+    * Read [[other:ssh#some_common_sense_advice|Do not forget your passphrase!]] if you need some advice about passphrases
+  * The best thing to do is probably to **keep the keys in the standard [[other:ssh#configuration_files|ssh configuration directory]]**!
+</WRAP>
+==== Converting existing ssh keys with PuTTYgen ====
+If you already have a private ssh key generated on another computer (e.g. an ''id_ed25519'' text file), you just have to use ''PuTTYgen'' to **import the existing private key**, and then export it to a //converted// ''id_ed25519.ppk'' file that ''Pageant'' can use
+  * Launch the ''PuTTY Key Generator'': ''Start'' => ''PuTTY'' => ''PuTTYgen''
+  * Import the key (and type the passphrase, when asked) with: ''Conversions''=>''Import key''\\ {{ :other:putty_21.png?direct&300 |}}
+  * Then click on the ''Save private key'' button, and create a ''id_ed25519.ppk'' file\\ {{ :other:putty_22.png?direct&300 |}}
+==== Creating ssh keys with PuTTYgen ====
+If you don't already have an existing set of //recent-enough// ssh keys, follow the steps below to **create a set of private and public keys**.
+Notes:
+  * by //recent-enough//, we mean ssh keys of type //rsa// and preferably //ed25519// (//dsa// is deprecated)
+  * extra technical details (that you can probably safely ignore) are available in the official [[https://the.earth.li/~sgtatham/putty/0.78/htmldoc/Chapter8.html#pubkey-puttygen|Using PuTTYgen, the PuTTY key generator]] documentation
+Steps:
+  * Launch the ''PuTTY Key Generator'': ''Start'' => ''PuTTY'' => ''PuTTYgen''
+  * Make sure that the selected //Type of key to generate// (at the bottom of the ''PuTTYgen'' window) is ''EdDSA'' (short for //Edwards-curve DSA//), with the default ''255'' bits.\\ This will generate **//ed25519// keys** that are now recommended on the IPSL servers
+    * {{:other:putty_23b.png?direct&500|}}
+    * You could also use ''RSA'' and ''4096'' bits, but ''ed25519'' keys are now recommended on the IPSL servers
+  * Click on the ''Generate'' button and move your mouse to generate some random information
+  * Type your ''Key passphrase'' and confirm it
+    * Read [[other:ssh#some_common_sense_advice|Do not forget your passphrase!]] if you need some advice about passphrases
+  * Click on the ''Save private key'' button, and create an ''id_ed25519**.ppk**'' file
+    * Note: files with a ''.ppk'' extension can only be used by ''PuTTY''/''pageant''. That's why you also need to //export// the private key, as shown below
-==== Importing or creating ssh keys with PuTTYgen ====
+  * **Important!** Click ''Conversions''=>''Export OpenSSH Key'' and create an ''id_ed25519'' file (a text file with **no** ''.ppk'' extension)
+    * You will not need this file when you use ''PuTTY'', but you may need to use this private key in a standard text format later, on Linux computers/servers
-  * Launch the PuTTY Key Generator:\\ ''Start'' => ''PuTTY'' => ''PuTTYgen''
+  * Open a text editor and create an ''id_ed25519**.pub**'' file
+    * Save the content of the ''Public key for pasting into OpenSSH authorized_keys file'' field in the file\\ Something looking like\\ <code>ssh-ed25519 AAAAC3NzaC1lZDI[... lots of characters ...]vwjLNmY eddsa-key-20230310</code>
-  * If you already have a private ssh keys generated on another computer, ''id_rsa'', you just have to use PuTTYgen to **import the private key**, and save it to a ''.ppk'' file that ''Pageant'' can use
+  * Click on the ''Save public key'' button, and create a ''id_ed25519**.pub**'' file
-    * Import the key (and type the passphrase, when asked) with: ''Conversions''=>''Import key''\\ {{ :other:putty_21.png?direct&300 |}}
+    * You will need to [[other:ssh#installing_ssh_keys|install the public key]] on all the remote Linux server that you want to connect to using the ssh agent, instead of typing your password
-    * Then click on the ''Save private key'' button, and create a ''id_rsa.ppk'' file (or ''any_name_you_want.ppk'')\\ {{ :other:putty_22.png?direct&300 |}}
-  * If you don't have a set of ssh keys, follow the steps below to **create private and public keys**
+==== Using the private key in Pageant ====
-    * Make sure that the type of key (at the bottom of the PuTTYgen window) is ''RSA'' and that the number of bits is ''4096''
-    * Click on the ''Generate'' button and move your mouse to generate some random information
-    * Type your ''Key passphrase'' and confirm it
-    * Click on the ''Save private key'' button, and create a ''id_rsa.ppk'' file (or ''any_name_you_want.ppk'')\\ {{ :other:putty_23.png?direct&300 |}}
-    * Click on the ''Save public key'' button, and create a ''id_rsa.pub'' file
-    * Click on ''Conversions''=>''Export OpenSSH key'', and create a (standard) ''id_rsa'' file\\ You will not need this file with Putty, but it is just in case you need to use your private key later on a Linux computer
+We assume that the **private key file** is available locally in ''<some_disk_different_from_c>:\Users\<your_login>\ssh\''
+  * Start ''Pageant'' and open the ''Pageant Key List'' window by:
+    * Double-clicking (left mouse button) on ''Pageant''
+    * Or right-clicking on ''Pageant'' and choosing ''View keys''
+  * Click on ''Add Key'', navigate to the directory where you have stored the ''.ppk'' converted private key file (e.g. ''\Users\<your_login>\ssh\''), open it and type your passphrase. You can ''Close'' the ''Pageant Key List'' once the key appears there\\ {{ :other:putty_private.png?direct&300 |}}
+  * If everything was done correctly, you should now be able to open the //Sessions// defined in ''Pageant'', on remote servers where the **public key matching the private key** used in ''Pageant'' was [[other:ssh#installing_ssh_keys|installed correctly]]
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