mask were 255.255.255.128 instead, creating (Free web space) zones for the
mask were 255.255.255.128 instead, creating zones for the subnet 149.76.12.128 would be impossible, because there’s no way to tell DNS that the 12.76.149.in-addr.arpa domain has been split into two zones of authority, with hostnames ranging from 1 through 127, and 128 through 255, respectively. Running named named (pronounced name-dee) provides DNS on most Unix machines. It is a server program originally developed for BSD to provide name service to clients, and possibly to other name servers. BIND Version 4 was around for some time and appeared in most Linux distributions. The new release, Version 8, has been introduced in most Linux distributions, and is a big change from previous versions.42 It has many new features, such as support for DNS dynamic updates, DNS change notifications, much improved performance, and a new configuration file syntax. Please check the documentation contained in the source distribution for details. This section requires some understanding of the way DNS works. If the following discussion is all Greek to you, you may want to reread the section “How DNS Works”. named is usually started at system boot time and runs until the machine goes down again. Implementations of BIND prior to Version 8 take their information from a configuration file called /etc/named.boot and various files that map domain names to addresses. The latter are called zone files. Versions of BIND from Version 8 onwards use /etc/named.conf in place of /etc/named.boot. To run named at the prompt, enter: # /usr/sbin/named named will come up and read the named.boot file and any zone files specified therein. It writes its process ID to /var/run/named.pid in ASCII, downloads any zone files from primary servers, if necessary, and starts listening on port 53 for DNS queries. 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 BIND 4.9 was developed by Paul Vixie, paul@vix.com, but BIND is now maintained by the Internet Software Consortium, bind- bugs@isc.org.