Prepare for ssh without a screen

Question

I have a Raspberry Pi model B at home, but I do not have a screen. My plan is to connect it to the ethernet and then ssh into it. But this means that the SD card with the operating system (Debian Squeeze) has to be prepared first. I see two ways:

1. Prepare the SD with the OS such that the RPi always connects to the ethernet under a fixed IP adress and enables an ssh server.

2. Prepare the SD with the OS such that the RPi connects to the network, enables an ssh server and then broadcasts its IP so that I can ssh into it.

Which of these ways is easier? And how do I do it? Are there other ways?

I have the following tools: Ubuntu 10.4, MacOS 10.5, Windows 7, but only the Ubuntu has a cardreader. Unfortunately I cannot access my router's DHCP table, it is completely closed.

Answer 1

To enable ssh at startup, backup boot.rc on the boot partition on the SD image and replace it with boot_enable_ssh.rc

I don't know about your router, but you may be able to configure it to reserve a fixed IP address for the MAC address of your Pi.

Answer 2

1. Copy boot_enable_ssh.rc to boot.rc from your /boot in Pi rootfs (SD card)

2. Still in your Pi rootfs edit your /etc/network/interfaces in order to have a fixed IP address assigned (so no dhcp server is needed). Ex:

   auto lo eth0
   iface lo inet loopback
   iface eth0 inet static
       address 192.168.0.202
       netmask 255.255.255.0
       gateway 192.168.0.200
   

3. Boot your Pi, use an ethernet cable to connect it to the same network that your PC is connected (or connect it direct to your PC) and login via SSH:

   ssh pi@192.168.0.202
   

4. Install a light VNC server in your Pi:

   sudo apt-get install tightvncserver
   

5. Then start the VNC server (you'll be asked to set a password):

   vncserver :1 -name RasPi -depth 16 -geometry 1024x768
   

6. Install a VNC client in your PC:

   apt-get install xtightvncviewer
   

7. Then connect to your Pi via VNC from your PC:

   xtightvncviewer 192.168.0.202:1
   

just works here in that way :)

Answer 3

If you use Arch distribution, you just plug it in and wait for it to get its address assigned from a DHCP. You can then check the DHCP's status (by connecting to your router for example) and retrieve the IP from connected clients list. If that fails, you can use nmap or similar tools to scan the entire subnet for open port 22 (SSH is enabled by default).

Answer 4

None of the boot_enable_ssh.rc stuff exists in current Raspian builds. You boot, a nice graphical menu gives you some options (including whether SSHD should load at boot) and then dumps you out on a command line.

That's great if... you're a graphical user.

If you're not, you're left in the position where you have to somehow externally run update-rc.d. All this really does is create a symlink to the /etc/init.d/... script at various points in the /etc/rc{0..6}.d/... filesystem. Confused? Never mind — doing the damage is simple.

1. I'm assuming you're doing this from a Linux computer. At least something using bash, or something compatible. What I'm suggesting will not work from Windows without Cygwin (or other). Mount the SD card and cd into it.

2. Run:

   for i in 2 3 4 5; do sudo ln -s /etc/init.d/ssh etc/rc$i.d/S02ssh; done
   

3. Unmount, and boot. You should have access to it over SSH.

If you're struggling to find it on your network...

Three options for you:

• Use your router's admin to find it. Netgear is especially good at showing "Attached Devices".
• Plug a monitor in and run ifconfig (cheating!)

• Use nmap on another computer to scan for it. You should know what IP it roughly has (to a /24) so scanning is simple:

  sudo nmap -sV --open 192.168.0.0/24  -p22
  

Answer 5

Using the Debian Wheezy beta image, SSH is installed and enabled by default. You just need to connect to it via its IP.

There are a few ways to work out what IP the RPi is on without having to run ifconfig on it directly, for example:

• Your router configuration pages may have a screen stating IP addresses for machines connected
• Most smartphones have free Wifi network scanners that will show devices connected to a network.

Answer 6

The easy way (if you have just a keyboard)

SSH is not enabled by default in Debian Wheezy (Raspbian). Enabling it is very simple, a lot simpler than most of the answers I've seen here, if you have a USB keyboard:

1. Plug in the keyboard and boot the RPi
2. Wait a minute, then type "pi", hit Enter, then "raspberry", and hit enter.

3. Enable SSH with:

   sudo /etc/init.d/ssh start
   

4. Type the password "raspberry" again just in case, since it's a sudo command, and hit Enter.

You should now be able to remote into your RPi by its IP address on your network.

As Denis Mitropolskiy mentioned, the configuration utility makes it easy to configure SSH at this point:

sudo raspi-config

Just go to the "ssh" option. Fortunately, this works in an SSH session, so the only command you need to run "blindly" is the first one above.

Answer 7

Can't say whether or not SSH works out of the box, but the latest configuration utility version has "Enable SSH" command. After that I was able to connect to my Raspberry via network . But to enable it you need a monitor anyway.

Answer 8

One caveat: With Arch Linux, this worked for me only if I had the ethernet hooked up before booting the RPi (and then it worked fine: sshd was enabled by default). If I first boot, then connect the ethernet cable, the RPi never contacts the DHCP server to get an ip address.

Answer 9

If you use Debian, then it's quite easy if you can lend a screen and network for your RPi for just some minutes from a friend. If not, you could just test the commands for 'nmap' and 'ssh' from your Ubuntu host.

Just check that the package openssh-server are installed, and you are up and going. You do that from the command line with aptitude install openssh-server. You could also check or rename the RPi when your are logged into the machine. You could also check that the package avahi-utils and avahi-daemon are installed, just try aptitude install avahi-utils.

The avahi package/program will implement Apples protocoll mDNS/DNS-SD which will announce itself to other computers that uses that protocoll as a computer in the DNS domain local. So if your machine is called rpi-machine, try to connect to the machine with rpi-machine.local.

You could check in the file /etc/nsswitch.conf to see if you have this line there:

hosts:          files mdns4_minimal [NOTFOUND=return] dns mdns4

Both your Apple and Ubuntu machine should implement this. Your MS Windows 7 machine doesn't do that though. On the Ubuntu machine you could try this command:

avahi-browse --all

or

avahi-browse _ssh._tcp

You should then get all your machines and their services, like SSH and HTTP listed.

You could also try to install the package nmap in your Ubuntu machine. Then can you check which net you are on with the command ip route list to see which IP-net you are on. For example on my machine I could get something like this (this is from example.com, so don't use it):

192.0.43.0/24 dev eth0  proto kernel  scope link  src 192.0.43.1  metric 1

tells me that I am on net 192.0.43.0/24 and the router are 192.0.43.1. So if you run the command nmap 192.0.43.0/24 will try to find all machines in your net and tell which ports are open. Look for port 22/tcp, as that are the ssh servers.

Answer 10

http://blog.marxy.org/2012/06/headless-raspberry-pi-on-network.html

To find the IP address of the Pi, try arp -a.