Python for Unix and Linux System Administration

Chapter 14. Pragmatic Examples

Managing DNS with Python

Managing a DNS server is a fairly straightforward task compared to, say, an Apache configuration file. The real problem that afflicts data centers and web hosting providers, though, is performing programatic large-scale DNS changes. It turns out that Python does quite a good job in this regard with a module called dnspython. Note there is also also another DNS module named PyDNS, but we will be covering dnspython.

Make sure you refer to the official documentation: http://www.dnspython.org/. There is also a great article on using dnspython here: http://vallista.idyll.org/~grig/articles/.

To get started using dnspython, you will only need to do an easy_install as the package is listed in the Python Package Index.

 ngift@Macintosh-8][H:10048][J:0]# sudo easy_install dnspython
 Password:
 Searching for dnspython
 Reading http://pypi.python.org/simple/dnspython/
 [output supressed]

Next, we explore the module with IPython, like many other things in the book. In this example, we get the A and MX records for http://oreilly.com:

In [1]: import dns.resolver
In [2]: ip = dns.resolver.query("oreilly.com","A")
In [3]: mail = dns.resolver.query("oreilly.com","MX")
In [4]: for i,p in ip,mail:
....:     print i,p
....:     
....:     
208.201.239.37 208.201.239.36
20 smtp1.oreilly.com. 20 smtp2.oreilly.com.

In Example 14-1, we assign the “A” record results to ip and the “MX” records to mail. The “A” results are on top, and the “MX” records are on the bottom. Now ...