Network Configuration

This section mainly introduces the methods for modifying the wired and wireless network configurations of the development board.

Wired Network

The default wired network configuration of the development board uses static IP configuration, and the initial IP address is 192.168.1.10. Users can switch between static and DHCP modes by the following methods.

Modifying Static IP Configuration

The development board's static network configuration is saved in the /etc/network/interfaces file. By modifying the address, netmask, gateway, and other fields, the static IP configuration can be modified. metric is the network priority configuration, setting it to 700 is to lower the priority of the wired network. When both wired and wireless networks are enabled, the wireless network will be prioritized. For example:

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sudo vim /etc/network/interfaces

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# interfaces(5) file used by ifup(8) and ifdown(8)
# Include files from /etc/network/interfaces.d:
source-directory /etc/network/interfaces.d
auto eth0
iface eth0 inet static
    address 192.168.1.10
    netmask 255.255.255.0
    gateway 192.168.1.1 
    metric 700

After the modification is completed, enter the command sudo restart_network on the command line to make the configuration take effect.

Modifying DHCP Configuration

DHCP (Dynamic Host Configuration Protocol) is usually applied in local area network environments. Its main function is centralized management and allocation of IP addresses, allowing hosts in the network environment to dynamically obtain IP addresses, gateway addresses, DNS server addresses, and other information, thereby improving the utilization of addresses.

The development board's DHCP network configuration is saved in the /etc/network/interfaces file. By modifying the relevant configuration of eth0, the DHCP mode can be modified. For example:

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sudo vim /etc/network/interfaces

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source-directory /etc/network/interfaces.d
auto lo
iface lo inet loopback
auto eth0
iface eth0 inet dhcp
metric 700

After modifying, enter the sudo restart_network command in the command line to make the configuration take effect.

Modify MAC address configuration

If you need to modify the default MAC address of the development board, you can add pre-up configuration information in the /etc/network/interfaces file to specify the MAC address you need, for example:

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sudo vim /etc/network/interfaces

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# interfaces(5) file used by ifup(8) and ifdown(8)
# Include files from /etc/network/interfaces.d:
source-directory /etc/network/interfaces.d
auto eth0
iface eth0 inet static
    address 192.168.1.10
    netmask 255.255.255.0
    gateway 192.168.1.1 
    pre-up ifconfig eth0 hw ether 00:11:22:9f:51:27

After modifying, reboot to make the configuration take effect.

Wireless Network

The development board integrates a 2.4GHz wireless WiFi module, which supports Soft AP and Station modes, and runs in Station mode by default. The following introduces how to use the two modes.

Station Mode

In Station mode, the development board as a client and accesses the router's wireless hotspot for internet connection.

• For users of Ubuntu Desktop version, you can click on the Wi-Fi icon in the upper right corner of the desktop, select the corresponding hotspot, and enter the password to complete the network configuration, as shown in the figure below:

• For users of Ubuntu Server version, you can complete the wireless network configuration through the command line, following these steps:

1. Use the sudo nmcli device wifi rescan command to scan for hotspots. If you get the following message, it means scanning is too frequent and you need to try again later:

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   root@ubuntu:~# sudo nmcli device wifi rescan
   Error: Scanning not allowed immediately following previous scan.
   

    

2. Use the sudo nmcli device wifi list command to list the scanned hotspots.

3. Use the sudo wifi_connect "SSID" "PASSWD" command to connect to the hotspot. If you get the following message, it means the network connection is successful:

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   root@ubuntu:~# sudo wifi_connect "WiFi-Test" "12345678" 
   Device 'wlan0' successfully activated with 'd7468833-4195-45aa-aa33-3d43da86e1a7'.
   

    

tip

If you receive the following message after connecting to the hotspot, it means the hotspot is not found. You can execute the sudo nmcli device wifi rescan command to rescan and reconnect.

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root@ubuntu:~# sudo wifi_connect "WiFi-Test" "12345678" 
Error: No network with SSID 'WiFi-Test' found.

Soft AP Mode

By default, the development board's wireless network runs in Station mode. To use the Soft AP mode, please follow the steps below for configuration.

1. Install hostapd and isc-dhcp-server

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   sudo apt update
   sudo apt install hostapd
   sudo apt install isc-dhcp-server
   

    

2. Run the command sudo vim /etc/hostapd.conf to configure the hostapd.conf file, focusing on the following fields:

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   interface=wlan0 # The network card used as an AP hotspot
   ssid=Sunrise # WiFi name
   wpa=2 # 0 for WPA, 2 for WPA2, usually 2
   wpa_key_mgmt=WPA-PSK # Encryption algorithm, usually WPA-PSK
   wpa_passphrase=12345678 # Password
   wpa_pairwise=CCMP # Encryption protocol, usually CCMP
   

    

   • For an open hotspot configuration, add the following content to the hostapd.conf file:

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   interface=wlan0
   driver=nl80211
   ctrl_interface=/var/run/hostapd
   ssid=Sunrise
   channel=6
   ieee80211n=1
   hw_mode=g
   ignore_broadcast_ssid=0
   

    

   • For a hotspot with a password, add the following content to the hostapd.conf file:

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   interface=wlan0
   driver=nl80211
   ctrl_interface=/var/run/hostapd
   ssid=Sunrise
   channel=6
   ieee80211n=1
   hw_mode=g
   ignore_broadcast_ssid=0
   wpa=2
   wpa_key_mgmt=WPA-PSK
   rsn_pairwise=CCMP
   wpa_passphrase=12345678
   

    

3. Configure the isc-dhcp-server file as follows:

   • Execute sudo vim /etc/default/isc-dhcp-server to modify the isc-dhcp-server file and add the following definition for the network interface:

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   INTERFACESv4="wlan0"
   

    

   • Execute sudo vim /etc/dhcp/dhcpd.conf to modify the dhcpd.conf file and uncomment the following fields:

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   authoritative;
   

    

   • Then, add the following configuration to the end of the /etc/dhcp/dhcpd.conf file:

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   subnet 10.5.5.0 netmask 255.255.255.0 { #network and subnet mask
   range 10.5.5.100 10.5.5.254;#IP range available
   option subnet-mask 255.255.255.0; #subnet mask
   option routers 10.5.5.1;#default gateway
   option broadcast-address 10.5.5.31;#broadcast address
   default-lease-time 600;#default lease time in seconds
   max-lease-time 7200;#maximum lease time in seconds
   }
   

    

4. Stop the wpa_supplicant service and restart wlan0

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   systemctl stop wpa_supplicant
   
   ip addr flush dev wlan0
   sleep 0.5
   ifconfig wlan0 down
   sleep 1
   ifconfig wlan0 up
   

    

5. Start the hostapd service as follows:

   • Execute the command sudo hostapd -B /etc/hostapd.conf

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   root@ubuntu:~# sudo hostapd -B /etc/hostapd.conf
   Configuration file: /etc/hostapd.conf
   Using interface wlan0 with hwaddr 08:e9:f6:af:18:26 and ssid "sunrise"
   wlan0: interface state UNINITIALIZED->ENABLED
   wlan0: AP-ENABLED
   

    

   • Configure the IP and subnet of wireless interface wlan0 using the ifconfig command, make sure it matches the configuration in the third step

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   sudo ifconfig wlan0 10.5.5.1 netmask 255.255.255.0
   

    

   • Finally, start the dhcp server. Clients connecting to the hotspot will be assigned an IP address from 10.5.5.100 to 10.5.5.255

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   sudo ifconfig wlan0 10.5.5.1 netmask 255.255.255.0
   sudo systemctl start isc-dhcp-server
   sudo systemctl enable isc-dhcp-server
   

    

6. Connect to the hotspot on the development board, for example, sunrise

   

7. If you need to switch back to Station mode, you can do it as follows:

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   # Stop hostapd
   killall -9 hostapd
   
   # Clear the address of wlan0
   ip addr flush dev wlan0
   sleep 0.5
   ifconfig wlan0 down
   sleep 1
   ifconfig wlan0 up
   
   # Restart wpa_supplicant
   systemctl restart wpa_supplicant
   
   # Connect to the hotspot, for specific operation, please refer to the previous section "Wireless Network"
   wifi_connect "WiFi-Test" "12345678"