Hardware Reference
In-Depth Information
If you need to return to automatic settings via DHCP, you need to edit the
interfaces
ile
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 identiier 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.
he 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 ile is automatically illed 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
ile (described earlier in this chapter).
To set the nameservers, open the ile 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
coniguration 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 ininite loop of
trying to ind a nameserver to ask how it can ind the nameservers.
Save the ile 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
