Use PuTTYgen generate PublicKey and PrivateKey

using PuTTYgen generate a pair of RSA PublicKey and PrivateKey

Step 1: generate and save PublicKey and PrivateKey

[note]Please generate some randomness by moving the mouse over the blank area.

1. mouse left click the “Generate” botton;
2. change the “Key comment” to userdefine-rsa-key-yyyymmdd；
3. mouse click the “Save private key” botton, click Yes to save *.ppk file,Not save in the CN_zh characters path,file name Not need to setting sufix-filename to *.ppk,system automaticlly setting;
4. mouse click the “Conversions”-> “Export OpenSSH key”,click Yes to save *.pemfile,NOTE need manually setting sufix-filename to *.pem;
5. Copy the contain in “Public key for pasting into OpenSSH authorized_keys file:”,such as:“ssh-rsa XXXX+XXXX+XXXX+XXXX+XXXX+XXXX usedefine-rsa-key-yyyymmdd” to the system clipboard.

Step 2: Create user and change SSH configure

1. mouse click the “Category”-> “Session”->"HostName(or IP address) input window,enter the Public IP;Not click the “Open” botton or press the “Enter” in keyboard;
2. mouse click the “Category”->“Connection”->“SSH”->“Auth”->“Browse…”,select the associate *.ppk file in system path;

Step 3:configure SSH Server in Redhat Linux

1. add username for Redhat

   $ sudo /usr/sbin/useradd username_demo

2. switch user to this new username

   $ sudo su - username_demo

3. copy and paste the PublicKey to the file: ~/.ssh/authorized_keys

   $ vim ~/.ssh/authorized_keys

   note, use vi to paste the PublicKey:
   1. press i enter the insert mode;
   2. press Shift+Insert to paste the PublicKeys from PuTTY in windows10 ;
   3. press Esc to exit insert mode;
   4. press :wq! to write to file + quit vi + force execute.

   change file to root read/write only

   $ chmod 600 ~/.ssh/authorized_keys

4. enable username to the allow list in sshd_config file

   $ sudo vim /etc/ssh/sshd_config

   add "AllowUsers username_demo " in the sshd_config file last line, such as:

   # Exampl mple of overriding settings on a per-user basis
   #Match User anoncvs
   #       X11Forwarding no
   #       AllowTcpForwarding no
   #       PermitTTY no
   #       ForceCommand cvs server
   
   # Allow username list
   AllowUsers username_demo
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Step 4: vncserver multiple users

1. create the associate config file for each username:
   The number in the symbol @ is the vncserver dispaly number, the port 5900 + sequence number(such as 5901). each run ** systemctl start vncserver@:1**,start a new vncserver port increase 1 in the before.

   $ cp /lib/systemd/system/vncserver@.service /etc/systemd/system/vncserver@:1.service
   $ cp /lib/systemd/system/vncserver@.service /etc/systemd/system/vncserver@:2.service

2. replace the in the Template file:

   1. setting the vncserver@:1.service for the root

      $ vim /etc/systemd/system/vncserver@:1.service

      press “:%s//root/g”, to replace all in this file, and press “:x” to save and quit vi.

   2. the same operator to the username_demo in the “/etc/systemd/system/vncserver@:2.service” file.

3. start the service:
   type below command in terminal:

   sudo systemctl daemon-reload
   sudo systemctl start vncserver@:1 # start a vncserver display for user: root
   sudo systemctl start vncserver@:2 # start a vncserver display for user: username_demo
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   other, vncserver common command:

   vncserver -list
   vncpasswd
   vncserver -kill :1