Contents
Authenticated connection with SSH key pair
Creation of public and private key pairs
Create a public/private key pair for a user connecting to a Linux server using OpenSSH.
Use ssh-keygen to create the key pair.
The creation of a public/private key pair is performed with the authority of the user logging in remotely.
If you do not specify the creation destination and file name, id_ed25519 and id_ed25519.pub will be created in /home/(user name)/.ssh/. On the way, also enter the password for the key.
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# su - huong [huong@Lepard ~]$ ssh-keygen -t ed25519 Generating public/private ed25519 key pair. Enter file in which to save the key (/home/huong/.ssh/id_ed25519): [Enter] Created directory '/home/huong/.ssh'. Enter passphrase (empty for no passphrase): [Password] Enter same passphrase again: [Paswword] Your identification has been saved in /home/huong/.ssh/id_ed25519 Your public key has been saved in /home/huong/.ssh/id_ed25519.pub The key fingerprint is: SHA256:ZP0Q7Ct0yAvtur00Zr2L2wQNmZVddrPoZ4ZyHFvq888 huong@Lepard The key's randomart image is: +--[ED25519 256]--+ | .oo .o..| | =o.....o| | o*oo o o | | .o=oooo * | | +So.o.B + | | +o. + + | | .=.o o | | .= = . o. | | ..=o+. .E| +----[SHA256]-----+ |
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$ cat ~/.ssh/id_ed25519.pub >> ~/.ssh/authorized_keys $ chmod 600 ~/.ssh/authorized_keys $ chmod 700 ~/.ssh/ |
Save the created private key id_ed25519 to an appropriate location on windows using winSCP.
Start Winscp and click "New Session"
![](https://korodes.com/wp-content/uploads/2022/12/737c880cf38e19da38e4ca18910e808b.jpg)
Host name : Server IP Address
Port number : SSH Port
User name : Server Login User
Password : Password for the same user
「Save」
![](https://korodes.com/wp-content/uploads/2022/05/f255feed548a8a69e94c283249a4c314.png)
Site name : Any name Click "OK"
![](https://korodes.com/wp-content/uploads/2022/12/095d894526d9a213f66932e161d8af60.jpg)
After confirming the server, click "Login".
![](https://korodes.com/wp-content/uploads/2022/12/7437cad40dc754312ab0553770234130.jpg)
Click "Update" when the following screen appears
![](https://korodes.com/wp-content/uploads/2022/12/2e00fae780c6e2620275e400efcbf03c.jpg)
Password of the logged-in user in the Password field
![](https://korodes.com/wp-content/uploads/2022/12/b54c0a7b8bf483337b3721315071a86a.jpg)
When connected, the right column is the server side and the left column is the PC (Windows) side.
Save the file "id_ed25519" in the .ssh directory to an appropriate location on Windows in the left column.
![](https://korodes.com/wp-content/uploads/2022/12/619dbc54004c69cdf80609f65223b403.jpg)
Editing SSH Configuration File
Edit the SSH configuration file to disable password authentication.
This time, use su - to become root instead of a normal user.
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$ su - Password: # vi /etc/ssh/sshd_config # Line 66 : Changed to no password authentication PasswordAuthentication no # systemctl restart sshd |
How to connect using Tera Term
Start Tera Term, and select "File" menu "New connection"
![](https://korodes.com/wp-content/uploads/2022/12/69db351a2f2c92e4701f73d55fa1b300.jpg)
Host : Server IP Address
TCP port : SSH Port
![](https://korodes.com/wp-content/uploads/2022/09/cbe504a8558fe1d751d7a493a163df52.png)
If you get the following security warning "Replace…." and click "Continue".
![](https://korodes.com/wp-content/uploads/2022/12/b79c07d75e313d1c1d72f47f0a1e96c8.jpg)
User name : Login User Name
Password :Password specified in the creation of a public/private key pair
Set "Use RSA/DSA/ECDSA/ED25519 key to log in" and "Private key file:" to "id_ed25519" saved in Windows earlier, and click "OK"
![](https://korodes.com/wp-content/uploads/2022/11/276eb927bdf1a8bc29fdda12410c485d.jpg)
Creating a private key using PuTTYgen
Start Winscp and launch Run Puttygen from "Tools".
Click Load
![](https://korodes.com/wp-content/uploads/2022/11/116a0f5ebc2b534bbc2bed990bd9b5bb.jpg)
The Open File dialog box will open. and load the private key id_ed25519 transferred from the Linux server
![](https://korodes.com/wp-content/uploads/2022/12/833a151d8ebf45f1aafb2dcd86af6c30.jpg)
The password is the password set in "Creating a public and private key pair" above
![](https://korodes.com/wp-content/uploads/2022/12/e9b6cf91492c969f7297d2222ba7a560.jpg)
Click "OK"
![](https://korodes.com/wp-content/uploads/2022/11/21b465931244151e5d4cc6c39aab389b.jpg)
Click on "Save private key"
![](https://korodes.com/wp-content/uploads/2022/12/d3a63fe1cf1830fafcc39f0518911b40.jpg)
Save the file with the extension ".ppk" in the same place as "id_ed25519" saved earlier on the Windows side under the name "id_ed25519.ppk".
![](https://korodes.com/wp-content/uploads/2022/12/124caa7129db3a340bf3ea5bafeb5327.jpg)
Select the appropriate server and click "Edit"
![](https://korodes.com/wp-content/uploads/2022/11/a1d71ba21e2d1fab2a461419e2725242.jpg)
Click on "Advanced"
![](https://korodes.com/wp-content/uploads/2022/11/c9dce692932a772488ad24abeb0426cc.jpg)
Open the "Authentication" menu and specify "id_ed25519.ppk" saved in Windows for "Private key file"
![](https://korodes.com/wp-content/uploads/2022/11/b243a3f21421d40287be72402061e4d7.jpg)
Click "Save"
![](https://korodes.com/wp-content/uploads/2022/11/b7a3029199cf31df0a9541e3523a7bb7.jpg)
Click on "Login"
![](https://korodes.com/wp-content/uploads/2022/11/98944ac66c50bb74fda4f33b465d7c38.jpg)
The password is the password set in "Creating a public and private key pair" above
![](https://korodes.com/wp-content/uploads/2022/12/2c76a6677b6352ef6b1a80010e3adb1f.jpg)
When connecting with Tera Term
In the "Use RSA/DSA/ECDSA/…" field, specify "id_ed25519.ppk" saved in windows.