hesiod.conf —
configuration file for the Hesiod library
The file hesiod.conf determines the behavior of the
  Hesiod library. Blank lines and lines beginning with a ‘#’
  character are ignored. All other lines should be of the form
  variable = value, where the value
  should be a single word. Possible variables and values are:
  - lhs
- Specifies the domain prefix used for Hesiod queries. In almost all cases,
      you should specify
      “lhs=.ns”. The
      default value if you do not specify an lhs value is no domain prefix,
      which is not compatible with most Hesiod domains.
- rhs
- Specifies the default Hesiod domain; this value may be overridden by the
      HES_DOMAINenvironment variable. You must specify
      an rhs line for the Hesiod library to work
    properly.
- classes
- Specifies which DNS classes Hesiod should do lookups in. Possible values
      are IN (the preferred class) and
      HS (the deprecated class, still used by some sites).
      You may specify both classes separated by a comma to try one class first
      and then the other if no entry is available in the first class. The
      default value of the classes variable is
      “IN,HS”.
There default value for “lhs” should probably be more reasonable.