Operation Manual

When you’ve finished editing the file, press CTRL + O to save it, and then press CTRL + X to leave nano and return to the
terminal. To use your new network settings, restart the networking service by typing the following:
sudo /etc/init.d/networking restart
If you need to return to automatic settings via DHCP, you need to edit the interfaces file again and delete the address,
netmask and gateway settings. Replace static with dhcp at the end of the iface line, and then restart the networking service
again.
Setting a manual IP address isn’t quite enough to get your Pi connected to the outside world. Computers on modern networks
have both a numerical address identifier known as an IP address and a hostname or domain name. It’s this latter, friendly name
which means you can simply type www.raspberrypi.org into your browser, instead of trying to remember 93.93.128.176.
A system called a Domain Name Service (DNS) server is responsible for looking up the friendly names you supply and
converting them into the numbers required to access the system. It operates much like an automated telephone directory. Before
you’ll be able to access Internet-connected systems via their domain names, you’ll need to tell the Pi which DNS servers to use.
The list of DNS servers, known as nameservers in Linux parlance, is stored in /etc/resolv.conf. When the system gets its
details through DHCP, this file is automatically filled in. When you set an address manually, you need to provide the addresses of
the nameservers on your network. Normally, this would be the address of your router as found in the gateway line from the
interfaces file (described earlier in this chapter).
To set the nameservers, open the file with nano by typing the following command at the terminal:
sudo nano /etc/resolv.conf
Add each nameserver on a separate line, prefaced with nameserver and a space. As an example, the resolv.conf
configuration for a network which uses Google’s publicly-accessible nameservers to resolve domain names would appear like
this:
nameserver 8.8.8.8
nameserver 8.8.4.4
You’ll notice that the nameserver addresses need to be supplied as IP addresses, rather than domain names. If you provided
domain names instead, the Pi would enter an infinite loop of trying to find a nameserver to ask how it can find the nameservers.
Save the file by pressing CTRL + O, and then quit nano by pressing CTRL + X. Restart the networking interface by typing the
following:
sudo /etc/init.d/networking restart