Network Working Group R. Arends
Internet-Draft S. Morris
Intended status: Informational J. Dickinson
Expires: May 22, 2008 Nominet
November 19, 2007
Name Server Control Protocol
draft-arends-nscp-00
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Abstract
This document describes the Name Server Control Protocol (NSCP). The
NSCP will permit the management of diverse name server
implementations. The NSCP uses NETCONF as framework.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Rationale . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Reserved Words . . . . . . . . . . . . . . . . . . . . . . 3
2. High level requirements . . . . . . . . . . . . . . . . . . . . 3
3. Approaches to Nameserver Control . . . . . . . . . . . . . . . 4
4. Data Model . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.1. A generic model . . . . . . . . . . . . . . . . . . . . . . 4
4.2. A Structured DNS model . . . . . . . . . . . . . . . . . . 5
5. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
6. Informative References . . . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
Intellectual Property and Copyright Statements . . . . . . . . . . 7
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1. Introduction
1.1. Rationale
Operators of name servers often deploy software from multiple
different vendors in order to reduce the threat from vulnerabilities
found in any single implementation. However, doing so requires
understanding a different control interface for each implementation.
Additionally, provisioning for name server clusters does not scale
well, since it often requires active lower level management of
individual hosts.
This document defines a DNS name server control protocol which will
permit management of multiple different name server implementations
via a common interface.
The NSCP will use NETCONF [1]as framework.
1.2. Reserved Words
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119.
2. High level requirements
The Protocol should:
o Enable the operation of all nameserver implementations
o Allow the (un)setting of all nameserver configuration parameters
o Be able to signal which operations are supported by the
implementation being controlled
o Allow the collection of any available nameserver statistics
o Be extensible to allow implementors to extend to cover new objects
and methods.
o Be able to handle any dns data that might be seen on the wire,
whether or not it is legal.
The requirements for the protocol are independent of the actual
functions that a nameserver implementation provides. Any operation
listed in this document does not require support for this function in
an implementation. It is RECOMMENDED however, that functions which
are supported by nameservers can be supported by this protocol,
either as a core function, or as part of the extentions.
The level of feedback, such as state, or statistics that an
implementation returns differs per implementation. This document
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does not dictate form or grammar of this feedback, but does allow the
transfer of this data. The extensibility of the protocol should be
rich enough to allow for various forms and ways of aggregating this
feedback.
3. Approaches to Nameserver Control
There have been several different approaches suggested for
controlling nameservers. Possibilities include, but are not limited
to, NETCONF, SNMP, some kind of in-band DNS based solution or a
totally new protocol. Whilst any of these solutions can work we
favor a solution based on NETCONF for the following reasons.
o It is based on XML.
o It operates persistent connections.
o It operates a command/response model.
o The protocol describes how error information is returned from the
agent to the client.
o It is extensible.
o It allows a client to discover the set of protocol extensions
supported by a server.
o It provides a separation of configuration and state data.
o It is designed to run on multiple different transports such as ssh
which have built-in strong authentication and encryption.
o It provides sophisticated searching capabilities.
4. Data Model
Netconf treats the contents of its configuration elements as opaque
data and assumes that the application will know what to do with it.
For this reason it is necessary to define a data model to contain DNS
configuration data. This data model will be required for use in NSCP
and may be of use to developers of future nameserver implementations.
There are several options for doing this, two of which are presented
here:
4.1. A generic model
A typical nameserver configuration file is made up of sections and
configuration items. A possible representation is shown in the
following fragment of XML:
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<file name="ns.conf">
<section name="server">
<configitem name="ip-address">10.0.0.1</configitem>
<configitem name="version">not available</configitem>
</section>
<section name="zone">
<configitem name="name">example.com</configitem>
<configitem name="zonfile">example.com.zone</configitem>
</section>
</file>
4.2. A Structured DNS model
Analysis of a range of nameserver configurations leads to a model
that is specific to DNS, such as:
Server
|
+------------+------------+
| |
PeerGroup Panorama
|1 |1
| |
|* 1 * |*
Peer ACL -------- View -------- Zone
|1 1 * |1
| |
|* |*
ACE RRSet
|1
|
|1..*
RR
^ --[ Inheritance symbol
|
|
Specific RR
In the above diagram, the names of the elements correspond to
standard DNS concepts, with the following additions:
o Peer - either a master or slave of the server in question.
o PeerGroup - the collection of Peers.
o Panorama - a collection of views.
5. Security Considerations
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6. Informative References
[1] Enns, R., "NETCONF Configuration Protocol", RFC 4741,
December 2006.
Authors' Addresses
Roy Arends
Nominet
Minerva House
Edmund Halley Road
Oxford Science Park
Oxford OX4 4DQ
UNITED KINGDOM
Phone: +44 1865 332211
Email: roy@nominet.org.uk
Stephen Morris
Nominet
Minerva House
Edmund Halley Road
Oxford Science Park
Oxford OX4 4DQ
UNITED KINGDOM
Phone: +44 1865 332211
Email: stephen.morris@nominet.org.uk
John Dickinson
Nominet
6 Nelson Close
OX10 0LG
UNITED KINGDOM
Phone: +44 7789485308
Email: jad@dickinson.co.uk
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