Bug#174360: DNS configuration section is inflexible

[Zefram <zefram@fysh.org>]

Package: install
Version: woody

I've installed Debian over the network.  Early in the install process,
dbootstrap asks for network and DNS configuration information, which is
used both for the network installation and as the initial configuration
of the installed system.

When asking for a hostname, dbootstrap rejects any hostname containing
dots; it demands an unqualified name.  This contradicts the reasonably
popular practice of making the hostname an FQDN, as promoted by Paul Vixie
in BIND documentation.  Obviously this doesn't make much difference to
the network install process, but it annoyingly forces the administrator
to modify this part of the configuration once the system is installed
and running.

The next configuration dialogue asks for "the domain name" of the network.
This is a rather confused request.  This information is actually used in
two distinct ways: to construct the host's FQDN, and to provide default
qualification for unqualified names in name lookups.  These two matters
are logically distinct, and, with the "search" directive replacing
"domain" in modern resolv.conf format, the default qualification need
not even be singular.

Secondly, the mention of "the network" seems to refer back to the IPv4
network-layer configuration that immediately precedes the DNS-related
configuration dialogues.  That might be accidental, a case of poor
proofreading, but I don't see what else could be being referred to by the
words "the network".  The domain part of the host FQDN, and the default
domain for unqualified names, needn't identify anything really meaningful,
such as a piece of network-layer topology or an administrative grouping.
All it can be said to identify is a group of related *names*, which I
wouldn't refer to as a "network".

(Incidentally, on perusal of the source I see that the domain name
dialogue doesn't check the domain name for validity with anything like
the stringency with which the hostname is checked.)

As a solution, I propose that the DNS configuration should ask the
following questions (with more explanation for those that don't know
the terminology):

     1. What is the hostname of this host?  You may give an unqualified
        or fully-qualified name.  [Default name is unqualified.
        Check for RFC1123 compliance, allowing but not requiring full
        qualification.  This is what goes in /etc/hostname.]

     2. [If hostname given was unqualified.]  What is the domain name
        that should be attached to the hostname to make the host's FQDN?
        [Default blank, which should be permitted.  If non-blank, this
        domain name is used to create an FQDN alias in /etc/hosts.]

     3. What domains should be searched to look up unqualified hostnames?
        [Default is the domain part of the host's FQDN, or "." if that
        is blank.  Permit multiple domain names.  A blank list is treated
        as ".".  The list goes into /etc/resolv.conf.]

-zefram