22.4 Starting the Name Server BIND
On an openSUSE® system, the name server BIND (Berkeley
Internet name domain) comes preconfigured so it can be started
right after installation without any problem. If you already have a
functioning Internet connection and have entered
127.0.0.1 as the name
server address for localhost
in /etc/resolv.conf, you normally already have a
working name resolution without needing to know the DNS of the provider.
BIND carries out name resolution via the root name server, a notably
slower process. Normally, the DNS of the provider should be entered with
its IP address in the configuration file
/etc/named.conf under
forwarders to ensure effective and secure name
resolution. If this works so far, the name server runs as a pure
caching-only name server. Only when you configure
its own zones will it become a proper DNS. A simple example of this is
included in the documentation in
/usr/share/doc/packages/bind/config.
HINT: Automatic Adaptation of the Name Server Information
Depending on the type of Internet connection or the network connection,
the name server information can automatically be adapted to the current
conditions. To do this, set the variable
MODIFY_NAMED_CONF_DYNAMICALLY in the file
/etc/sysconfig/network/config to
yes.
However, do not set up any official domains until assigned one by the
responsible institution. Even if you have your own domain and it is
managed by the provider, you are better off not using it, because BIND
would otherwise not forward requests for this domain. The Web server at
the provider, for example, would not be accessible for this domain.
To start the name server, enter the command
rcnamed start as
root. If done
appears to the right in green, named, as the name server process is
called, has been started successfully. Test the name server immediately
on the local system with the host or
dig programs, which should return
localhost as the default
server with the address
127.0.0.1. If this is not the
case, /etc/resolv.conf probably contains an
incorrect name server entry or the file does not exist at all. For the
first test, enter
host 127.0.0.1, which should
always work. If you get an error message, use
rcnamed status to see whether
the server is actually running. If the name server does not start or
behaves unexpectedly, you can usually find the cause in the log file
/var/log/messages.
To use the name server of the provider or one already running on your
network as the forwarder, enter the corresponding IP address or addresses
in the options section under
forwarders. The addresses included in
Example 22-1 are just examples. Adjust these entries to
your own setup.
Example 22-1 Forwarding Options in named.conf
options {
directory "/var/lib/named";
forwarders { 10.11.12.13; 10.11.12.14; };
listen-on { 127.0.0.1; 192.168.1.116; };
allow-query { 127/8; 192.168/16 };
notify no;
};
The options entry is followed by entries for the
zone, localhost, and
0.0.127.in-addr.arpa. The type
hint entry under .
should always be present. The
corresponding files do not need to be modified and should work as they
are. Also make sure that each entry is closed with a ;
and
that the curly braces are in the correct places. After changing the
configuration file /etc/named.conf or the zone
files, tell BIND to reread them with
rcnamed reload. Achieve the same
by stopping and restarting the name server with
rcnamed restart. Stop the server
at any time by entering
rcnamed stop.
