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 16-1 are just examples. Adjust these entries to your own setup.
Example 16-1 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.