6.3.1. The named.boot File
The BIND configuration file prior to Version 8 was very simple in structure. BIND Version 8 has a very different configuration file syntax to deal with many of the new features introduced. The name of the configuration file changed from /etc/named.boot , in older versions of BIND, to /etc/named.conf in BIND Version 8. We'll focus on configuring the older version because it is probably what most distributions are still using, but we'll present an equivalent named.conf to illustrate the differences, and we'll talk about how to convert the old format into the new one.
The named.boot file is generally small and contains little but pointers to master files containing zone information and pointers to other name servers. Comments in the boot file start with the (#) or (;) characters and extend to the next newline. Before we discuss the format of named.boot in more detail, we will take a look at the sample file for vlager given in Example 6-8 .
Example 6-8. The named.boot File for vlager
;
; /etc/named.boot file for vlager.vbrew.com
;
directory /var/named
;
; domain file
;-----------------
cache . named.ca
primary vbrew.com named.hosts
primary 0.0.127.in-addr.arpa named.local
primary 16.172.in-addr.arpa named.rev
Let's look at each statement individually. The directory keyword tells named that all filenames referred to later in this file, zone files for example, are located in the /var/named directory. This saves a little typing.
The primary keyword shown in this example loads information into named . This information is taken from the master files specified as the last of the parameters. These files represent DNS resource records, which we will look at next.
In this example, we configured named as the primary name server for three domains, as indicated by the three primary statements. The first of these statements instructs named to act as a primary server for vbrew.com , taking the zone data from the file named.hosts .
The cache keyword is very special and should be present on virtually all machines running a name server. It instructs named to enable its cache and to load the root name server hints from the cache file specified (named.ca in our example). We will come back to the name server hints in the following list.
Here's a list of the most important options you can use in named.boot :
- directory
- primary
- secondary
This option specifies a directory in which zone files reside. Names of files in other options may be given relative to this directory. Several directories may be specified by repeatedly using directory . The Linux file system standard suggests this should be /var/named .
This option takes a domain name and filename as an argument, declaring the local server authoritative for the named domain. As a primary server, named loads the zone information from the given master file.
There will always be at least one primary entry in every boot file used for reverse mapping of network 127.0.0.0 , which is the local loopback network.
This statement takes a domain name, an address list, and a filename as an argument. It declares the local server a secondary master server for the specified domain.
A secondary server holds authoritative data on the domain, too, but it doesn't gather it from files; instead, it tries to download it from the primary server. The IP address of at least one primary server thus must be given to named in the address list. The local server contacts each of them in turn until it successfully transfers the zone database, which is then stored in the backup file given as the third argument. If none of the primary servers responds, the zone data is retrieved from the backup file instead.
named then attempts to refresh the zone data at regular intervals. This process is
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