Configuring named to start automatically after every reboot

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The following might look a little complicated, read it twice if you feel that you don't understand what's going on here. Services are started by startup-scripts in the directory /etc/rc.d/init.d/. This is how we started named just a few minutes ago (depends how fast you are typing and reading …). Now we have to tell linux to start named automatically. You can use tools from x-windows, but since I like Linux because I don't need a graphic interface, we will do it by hand, without any special tool. If we run ls /etc/rc.d, we will see the following directories (among others): rc0.d, rc1.d, rc2.d, rc3.d, rc4.d, rc5.d, rc6.d

Each of those directories refers to a runlevel, for example rc3.d refers to runlevel three. Runlevels could be described as a state of the system. Look at the following table:

0

Halt the system

1

Enter single-user mode (no networking is enabled)

2

Multiuser mode, but without NFS

3

Full multiuser mode (normal operation)

4

Unused

5

Same as runlevel 3, except using an X Windows login rather than a text-based login

6

Reboot the system

To tell our linux system when to start which service, we would have to place a startup script in the corresponding directory. However, to make things not more complicated than they already are we will use symbolic links rather than a separate script file everytime. But just adding named to the rc3.d directory (standard runlevel our server should be in most of the time) is not enough. We have to tell linux in which order to start or stop the services.

Let's take a look at result of ls /etc/rc.d/rc3.d/:

K20nfs	K20rwalld	K20rwhod	K34yppasswdd
K45arpwatch	K45named	K84ypserv	S05kudzu
S08ipchains	S10network	S12syslog	S13portmap
S14nfslock	S16apmd	S20random	S25netfs
S35identd	S40atd	S45pcmcia	S50xinetd
S55sshd	S56rawdevices	S60lpd	S75keytable
S80sendmail	S85gpm	S85httpd	S90crond
S90xfs	S95anacron	S97rhnsd	S99linuxconf
S99local

         
The first letter, S, indicates that the script should be started. The 2^nd and 3^rd number tell the order where 01 would be the first service to start. The rest is the name of the script in the ../init.d/ directory. If we would configure a service to stop (such as in runlevels 0 and 6) we would use a K instead of a S at the beginning.

In our case I would tell named to start before xinetd, using the number 47. I will have named start in runlevels 3 and 5. So we type

ln –s /etc/rc.d/init.d/named /etc/rc.d/rc3.d/S53named
ln –s /etc/rc.d/init.d/named /etc/rc.d/rc5.d/S53named

To start named in runlevel 3 and 5 automatically. To stop named everytime we make a reboot or halt or system, we add the following if it doesn't already exist (please check)

ln –s /etc/rc.d/init.d/named /etc/rc.d/rc0.d/K45named
ln –s /etc/rc.d/init.d/named /etc/rc.d/rc6.d/K45named

Now reboot by typing

shutdown –r now

If we find named started automatically after the login, we are already 25% on our way. You can see if the process is active by typing ps –A | grep named

If we were going from San Diego to Miami, we would probably be somwhere in New Mexico.