Differences

This shows you the differences between two versions of the page.

--- other:putty_conf [2022/08/08 17:54] – [Changing some useful settings] Added link to X server page jypeter
+++ other:putty_conf [2023/03/15 14:53] – [Using ssh keys] More wise advice jypeter
@@ 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 |}}
@@ Line 120: / Line 120: @@
 <WRAP center round important 80%>
   * **Do not lose** the (existing) ssh keys files you have, or the keys that you will create
-    * It's a very good idea to **keep a copy of these files** on another computer!
+    * 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
-  * If you save the passphrase in a file, **do not** put this file in the same place as the ssh keys
+  * The best thing to do is probably to **keep the keys in the standard [[other:ssh#configuration_files|ssh configuration directory]]**!
-  * Easiest thing to do is probably to store the key files in an ''ssh'' sub-directory somewhere
-    * We assume below that they keys are in a sub-directory of your [[other:win10config#the_most_important_folders|local HOME FOLDER]]\\ \\ <some_disk_different_from_c>:\Users\<your_login>\ssh\
 </WRAP>
@@ Line 142: / Line 141: @@
 ==== Creating ssh keys with PuTTYgen ====
-If you don't have a set of ssh keys, follow the steps below to **create private and public keys**
+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
-  * Make sure that the type of key (at the bottom of the ''PuTTYgen'' window) is ''RSA'' and that the number of bits is ''4096''
+Steps:
+  * 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
-  * 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&400 |}}
+    * Read [[other:ssh#some_common_sense_advice|Do not forget your passphrase!]] if you need some advice about passphrases
-  * Click on the ''Save public key'' button, and create a ''id_rsa.pub'' file
+  * 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
+  * **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
+  * 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>
+  * Click on the ''Save public key'' button, and create a ''id_ed25519**.pub**'' file
     * 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
-  * 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
 ==== Using the private key in Pageant ====