4.6 Tools

Wouldn't it be handy to have a tool to translate your host table into name server file format? There is such a beast, written in Perl: h2n - a host table to name server file converter. You can use h2n to create your data the first time and then maintain your DNS data manually. Or, you can use h2n over and over again. As you have seen, the format of the host table is much simpler to understand and to modify correctly. So, you could maintain /etc/hosts and rerun h2n to update your DNS data after each modification.

If you plan to use h2n, you might as well start with it, since it uses /etc/hosts - not your hand-crafted DNS data - to generate the new DNS files. We could have saved ourselves lots of work by generating the sample data in this chapter with the following:

% h2n -d movie.edu -s terminator -s robocop \
  -n 192.249.249 -n 192.253.253 \
  -u al.robocop.movie.edu

(To generate a version 8 configuration file, add -v 8 to the option list.)

The -d and -n options specify the domain name and network numbers. You'll notice that the db filenames are derived from these options. The -s options list the name servers for the NS records. The -u (user) is the email address in the SOA record. We'll cover h2n in more detail in Chapter 7, after we've covered how DNS affects email.