kcd at daimlerchrysler.com
Thu Mar 3 00:43:09 UTC 2005
>i'm trying to setup a DNS server using named (BIND 9.2.3rc2).
>could anyone point me to some info that would explain the concepts of
>'zones' and how they need to be handled if you don't actually have a
>domain to manage (eg. soho network)?
Zones are like tables in a big database, that can be defined at any
juncture in the namespace hierarchy. The contents of a zone consist of
all records in a particular *domain* (e.g. example.com and everything
beneath it, e.g. foo.bar.example.com), minus the contents of any zones
that reside beneath (e.g. if blah.example.com is a zone, then the
example.com zone would not include any of the records contained in it,
ditto for any other subdomains which are delegated as zones unto
If you have no "domain to manage", i.e. if your nameserver is not
serving any zone content, then really the only zone you absolutely must
care about is the "root" zone, which is at the top of the namespace
hierarchy. At startup time, your BIND instance will attempt to determine
the servers of the root zone, and once it gets that info, as queries
come in to be resolved, it'll work its way down from there to various
parts of the namespace hierarchy to resolve them. The ways that BIND
gets this initial root-zone information is either a) by being
authoritative (master or slave) for the root zone (this is unlikely to
be an option for an Internet-resolving nameserver, but is doable in an
internal-root architecture), b) by forwarding to some other
nameserver(s), or c) by having a "." (i.e. root) zone of type "hint"
configured into it, where the "hints" zone file contains only the names
and addresses of root servers (BIND doesn't take the contents of the
"hints" file as gospel though: it generates "priming" queries to the
servers mentioned in the "hints" file to get the most current root-zone
information, and will generate a warning message if the contents of your
"hints" file does not match reality).
All of this is covered in the _DNS_and_BIND_ book from O'Reilly, which
is considered the "bible" on the subject...
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