Softpanorama (slightly skeptical) Open Source Software Educational Society

May the source be with you, but remember the KISS principle ;-)

DNS Zone Generators

No normal person will ever generate reverse zone manually. But forward zones are also not that great as bind syntax is pretty obscure and unless you use sophisticated features is an overkill.

Old News ;-)

[Feb 7, 2007] Everything Sysadmin / hostdb

Hostdb

A system for generating internal DNS zones, external DNS zones, and DHCP configuration data from the same hostlist.txt file. Keep your configurations consistant by generating them all from the same source. The files that are generated are beautifully formated and easy to "diff" before they are put into production. It even generates the Makefile required to make the system all work together. A "file push" mechanism (mkdestinations), plus many DNS-related utilities are included (sortbyip, genrange, comparezones, checkrootcache).

First unveiled at the Usenix LISA 2005 Conference, San Diego, December 4-9, 2005 under the title, "HostDB: The Best Damn host2DNS/DHCP Script Ever Written".

Released under the GPL on January 8, 2005. Current release: 1.002

• Join the mailing list: hostdb-fans
• View all the releases: releases

Update:

• 2008-02-06: 1.002 released. Improved genrange, canonzone, and adds HIDEMASTER and DOMAINMX keywords to zoneconf.txt. See README.txt and examples/goodstart/zoneconf.txt for more info.
• 2006-07-05: RPM available. Antoine Brenner as created a source rpm for centos4 (should be fine with most rpm-based distributions). link. Thanks Antoine!

Recommended Links

 A Survey of DNS Tools  An old slides by Cricket Liu

[PDF] 46 DNS

DNSTool

DNStool 2.2 administration guide

The Domain Name Service (DNS) auto-configuration system (DNStool) is designed to take the pain out of managing DNS. It does this by automatically generating DNS files from a small number of configuration files. DNS files are in a complex and repetitious format; mistakes or omissions often creep in when manually maintained. In general, it reduces the task of maintaining DNS to 3 steps:

1. for each domain, maintain a database describing its hosts
2. maintain a description of the common features across domains
3. run the configuration programs to generate DNS configuration files and install them.

This document is aimed at DNS administrators and is a description of these three steps in modifying the configuration. The DNS autoconfiguration system does not remove the need to understand the basics of DNS (and the DNS auto-configurer) in order to make major changes to the DNS configuration

Download the tool

 

Generation of zones from /etc/hosts file

 

h2n, a tool for converting a static hosts file into DNS zone files. Originally written by Cricket Liu for the O'Reilly DNS and BIND book. Currently maintained by Hal Pomeranz.

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 -v 8 -d movie.edu -s terminator -s robocop -n 192.249.249 -n 192.253.253 -u al.robocop.movie.edu

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.

• manpage of h2n(1M)

• Draco - DNS config files
   

Reverse Zones Generation

mkrdns -- Program to automatically generate reverse DNS zone files (PTR records) Dec 03rd 1998, 10:34 stable: 1.4 - devel: none license: GPL

mkdnstab DNS Table generator in Perl Jul 10th 1999, 00:28 stable: 0.3 - devel: none license: OpenSource

Updatehosts ftp://ftp.tic.com/pub/updatehosts/updatehosts-1.0.0.tar.gz -- is a system for automatically managing and generating DNS zone files using flat relational tables. Some of the features of updatehosts includes:

• Automatic generation of DNS zone files including *.in-addr.arpa zones for an unlimited number of DNS zones.
• Automatic generation of BIND V4 or V8 bootstrap files with support for most BIND options.
• Automatic serial number generation in DNS zone files. Automatic generation of the DHCP bootstrap file.
• Limited support for DNS updates when using DHCP dynamic addressing.
• Generation of static hosts files from the same set of information used for DNS zone file generation
• Flexible input file syntax which allows additional information such as contact names, etc to be kept with all DNS information. This information can be added without impacting DNS zone file generation.
• Tools which allow a set of administrators to manage the the nameserver configuration without requiring root access.
• Conversion utilities to convert existing DNS zone files or static host tables into the updatehosts input file format.
• Flexible postprocessing hooks which allow site specific command to be run after the file generation is completed.
• General purpose tool for reading flat ASCII files as database relations.
• Maintenance of input files under SCCS or RCS control as a user option.T
• A mailing list (updatehosts@tic.com) has been set up. to subscribe send request to majordomo@tic.com.
   

Etc

dnsupdate  -- does not make any sense other then exercise in C

In search for a program that would help me create and maintain the DNS databases, my efforts were in vain. The nearest ones I could find were written in perl. The last thing I wanted to do from my program was to do a "system" call. I started playing with BIND 8.2.2 P7 and converted the nsupdate program to a function. That actually made me write the rest of the program.

My benchmark program was the famous h2n perl script. dnsupdate seems to be much faster than h2n. I have given a timing comparison table between dnsupdate and h2n in Appendix B. 

With my highly limited knowledge about DNS or its configuration files (DNS tables or DNS databases) I am requesting users of this program to pinpoint any errors or suggestions to make dnsupdate a better one.

Created May 16, 1996; Last modified: June 02, 2008