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Remote Access

SSH

This is a tutorial on how to access the board remotely from another computer using SSH.

View username

Open a terminal on the board and enter the following command in the terminal to view the username


  radxa@undefined:~$ whoami
  radxa
  

This command displays the username of the current user, as shown above, the current user's username is radxa

View IP address

View IP by command

Open a terminal on the board and enter the following command in the terminal to view the IP address:


  radxa@undefined:~$ ip a
  

The ip address on the same network segment as the host is the ip address we need for SSH connection, e.g. 192.168.2.100 in the following output is the ip address we need.

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
link/ether 56:ae:03:82:18:51 brd ff:ff:ff:ff:ff:ff:ff
inet 192.168.2.100/24 brd 192.168.2.255 scope global dynamic noprefixroute eth0
valid_lft 43176sec preferred_lft 43176sec
inet6 fe80::8e:d164:96ea:40b6/64 scope link noprefixroute
valid_lft forever preferred_lft forever
Finding IPs with Angryip

This method can be used to look up an ip address when you can't operate the motherboard directly to get an ip address without a screen or remotely.

  • First the host PC needs to download Angryip, then make sure the host PC and the board are on the same LAN.

  • Open Angryip, select the IP range from 192.168.2.0 - 192.168.2.255 (select the network segment where the host PC and the motherboard are located), click Start, as shown in the figure.

  • ! Angryip

  • Ctrl + F Look for the rock keyword to find the IP address of the board.

Checking SSH Service Status

Run the following command in a terminal:


  radxa@undefined:~$ sudo service ssh status
  

This command is used to view the status of the ssh service. If you run this command and are prompted with "Unit ssh.service could not be found.", then you need to install the SSH service.


  radxa@undefined:~$ sudo apt-get update
  radxa@undefined:~$ sudo apt-get install openssh-client openssh-server
  
● ssh.service - OpenBSD Secure Shell server
Loaded: loaded (/lib/systemd/system/ssh.service; enabled; preset: enabled)
Active: active (running) since Wed 2024-05-08 07:52:50 UTC; 24min ago
TriggeredBy: ● ssh.socket
Docs: man:sshd(8)
man:sshd_config(5)
Process: 637 ExecStartPre=/usr/sbin/sshd -t (code=exited, status=0/SUCCESS)
Main PID: 657 (sshd)
Tasks: 1 (limit: 3420)
Memory: 5.5M
CPU: 398ms
CGroup: /system.slice/ssh.service
└─657 "sshd: /usr/sbin/sshd -D [listener] 0 of 10-100 startups"

May 08 07:52:49 radxa-zero systemd[1]: Starting ssh.service - OpenBSD Secure Shell server...
May 08 07:52:50 radxa-zero sshd[657]: Server listening on :: port 22.
May 08 07:52:50 radxa-zero systemd[1]: Started ssh.service - OpenBSD Secure Shell server.
May 08 07:53:22 radxa-zero sshd[783]: Accepted password for radxa from 192.168.31.1 port 49474 ssh2
May 08 07:53:22 radxa-zero sshd[783]: pam_unix(sshd:session): session opened for user radxa(uid=1000) by (uid=0)
May 08 07:53:22 radxa-zero sshd[783]: pam_env(sshd:session): deprecated reading of user environment enabled
  • If the status of Active is active, the state of ssh is running.
  • If Active is inactive (dead), then ssh is stopped, i.e. the service is not running and needs to be restarted.

  radxa@undefined:~$ sudo service sshd restart
  

SSH connection to the board

ssh [username]@[IP address] # or ssh [username]@[hostname]

VNC

This is a tutorial on how to remotely access your system from a Windows computer using VNC.

Installing VNC Server

  1. Open the Terminal application and enter the following command to update the package list.

  radxa@undefined:~$ sudo apt-get update
  
  1. Install TigerVNC Server by entering the following command.

  radxa@undefined:~$ sudo apt-get install tigervnc-standalone-server
  
  1. Install the dbus-x11 dependency to ensure proper connection to your VNC server:

  radxa@undefined:~$ sudo apt-get install dbus-x11
  
  1. After installation to complete the initial configuration of your VNC server, use the vncserver command to set the security password and create the initial configuration file:

  radxa@undefined:~$ vncserver
  
note

Would you like to enter a view-only password (y/n)? n Prompt for view-only, would you like to select no and enter n so that you can operate remotely instead of just watching, depending on your situation?

Configuring the VNC Server

  1. Once TigerVNC starts, it will create a VNC session containing the IP address and port number (usually 5901) of the VNC server. To change the way the VNC server is configured, first stop the instance of the VNC server running on port 5901 with the following command:

  radxa@undefined:~$ vncserver -kill :1
  
  1. When you run the vncserver command, an xstartup is generated in the ~/.vnc directory. If it is not generated, please create it manually and give it executable permissions:

  radxa@undefined:~$ touch ~/.vnc/xstartup
  radxa@undefined:~$ chmod +x ~/.vnc/xstartup

Edit the xstartup configuration file as follows:


  radxa@undefined:~$ cat ~/.vnc/xstartup
  #!/bin/sh
  unset SESSION_MANAGER
  unset DBUS_SESSION_BUS_ADDRESS
  unset XDG_RUNTIME_DIR
  /etc/X11/xinit/xinitrc
  [ -x /etc/vnc/xstartup  ] && exec /etc/vnc/xstartup
  [ -r $HOME/.Xresources ] && xrdb $HOME/.Xresources
  xsetroot -solid grey
  #vncconfig -iconic &
  startkde &
  1. Once the configuration is edited, restart the VNC server:

  radxa@undefined:~$ vncserver -localhost no
  
  1. View the VNC server:

  radxa@undefined:~$ vncserver -list
  TigerVNC server sessions:
  X DISPLAY #	RFB PORT #	PROCESS ID	SERVER
  :1         	5901      	2160      	Xtigervnc
  :2         	5902      	2872      	Xtigervnc
  
  1. Test the connection on the VNC viewer: On your Windows PC, open the VNC viewer, enter the IP address and port number of your product, and then authenticate with the VNC server's username and password.

Installing the VNC Viewer on a Windows PC

  1. Go to the VNC viewer download page on your web browser, e.g. https://www.realvnc.com/en/connect/download/viewer/
  2. Download and install the VNC viewer.

Connection Setup

  1. On the VNC viewer, enter the IP address and port number of the product. 2.
  2. Use the VNC server's user name and password to authenticate.
  3. After a successful connection, you can remote control.

TeamViewer

Installing TeamViewer


  radxa@undefined:~$ wget https://download.teamviewer.com/download/linux/teamviewer-host_arm64.deb
  radxa@undefined:~$ sudo apt install . /teamviewer-host_arm64.deb
  

configure TeamViewer


  radxa@undefined:~$ sudo teamviewer setup    # Agree to protocol login and authorization
  

uninstall xfce4-screensaver

info

This procedure fixes a problem with TeamViewer's keyboard and mouse controls not working due to prolonged hang time.


  radxa@undefined:~$ sudo apt remove xfce4-screensaver
  

Configuring virtual monitors

info

This step is optional if a real monitor is connected.


  radxa@undefined:~$ sudo apt update
  radxa@undefined:~$ sudo apt install xserver-xorg-video-dummy
  radxa@undefined:~$ sudo mv /etc/X11/xorg.conf.d/20-modesetting.conf /etc/X11/xorg.conf.d/20-modesetting.bak
  radxa@undefined:~$ sudo nano /etc/X11/xorg.conf.d/10-headless.conf
# Add the following and reboot
Section "Monitor"
Identifier "dummy_monitor"
HorizSync 28.0-80.0
VertRefresh 48.0-75.0
Modeline "1920x1080" 172.80 1920 2040 2248 2576 1080 1081 1084 1118
EndSection

Section "Device"
Identifier "dummy_card"
VideoRam 256000
Driver "dummy"
EndSection

Section "Screen"
Identifier "dummy_screen"
Device "dummy_card"
Monitor "dummy_monitor"
SubSection "Display"
EndSubSection
EndSection

Connecting to TeamViewer

You can refer to TeamViewer official documentation.