Direct Ethernet connection to Raspberry Pi/Odroid without router (with DHCP, tested on Ubuntu 16.04)

Direct_ethernet_connection.md

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Direct Ethernet connection to Raspberry Pi/Odroid without router

The solution is based on running DHCP service at your workstation (your notebook for example), and use it to attribute an IP address to your Raspberry Pi/Odroid. Then use ssh to connect to your Raspberry Pi/Odroid through this IP address.

Terminology	Explaination
Client	Your Single Board Computer, such as a Raspberry Pi or an Odroid
Server	Your workstation with any linux based systems, like Ubuntu

Configuration at the Client Side (optional)

1. Enable SSH connection

• for Raspberry Pi

  sudo systemctl enable ssh

• for Odroid

  sudo vim /etc/ssh/sshd_config

  find the line PermitRootLogin and set it to PermitRootLogin yes

2. Modify DHCP Client configuration

   sudo vim /etc/dhcp/dhclient.conf
   

   fin the line send host-name "foo"; and uncommented it

Configuration at the Server Side

1. Install a DHCP server

   sudo apt-get install isc-dhcp-server
   

2. Use ifconfig to find your Ethernet network interface, it's probably eth0 but in my case it's enp61s0, then you need to configure a subnetwork on this interface

3. Backup your interface configuration file

   sudo cp /etc/network/interfaces /etc/network/interfaces.original
   

4. Modify interface configuration file

   sudo vim /etc/network/interfaces
   

   which should be modified like the output below

   auto lo
   iface lo inet loopback
   
   iface enp61s0 inet static
           address 192.168.1.1
           netmask 255.255.255.0
           network 192.168.1.0
   
   

5. Backup your configuration file of DHCP service

   sudo cp /etc/dhcp/dhcpd.conf /etc/dhcp/dhcpd.conf.original
   

6. Modify the configuration file of DHCP service

   sudo vim /etc/dhcp/dhcpd.conf
   

   which should be modified like the output below

   ddns-update-style	none;
   default-lease-time 3600;
   max-lease-time 7200;
   authoritative;
   
   subnet 192.168.1.0 netmask 255.255.255.0 {
     option routers 192.168.1.1;
     range 192.168.1.100 192.168.1.200;
   }
   

7. Start the DHCP service by typing

   # bring up the enp61s0 interface
   sudo ifup enp61s0 
   # start DHCP service
   sudo service isc-dhcp-server start
   # enable forwarding from the ethernet to wireless router
   sudo /sbin/iptables --table nat -A POSTROUTING -o wlan0 -j MASQUERADE
   

8. Now plug your Raspberry Pi or or Odroid and open another terminal and tape

   tail -f /var/log/sys/log
   

   to test the connection, you should see an entry like

   Dec 3 21:51:24 jzhou-Alienware-15-R3 dhcpd[10817]: DHCPACK on 192.168.1.100 to 00:1e:06:cb:e0:f5 (foo) via enp61s0

9. Then you can connect to your Raspberry Pi or or Odroid by

   • for Odroid ssh root@192.168.1.100
   • for Raspberry Pi ssh pi@192.168.1.100

Reference and Useful Resource

1. ODROID-C2 from scratch
2. How do I install and configure a DHCP server?
3. Serveur DHCP : isc-dhcp-server
4. Linux(非 ubuntu) 用一根网线连接树莓派
5. Ubuntu Linux Display List of Ethernet Adapter
6. Connecting a Raspberry Pi to a ubuntu netbook