wdiff draft-woodworth-bulk-rr-06.txt draft-woodworth-bulk-rr-07.txt

DNSOP Working Group J. Woodworth
Internet-Draft D. Ballew
Obsoletes: 222 (if approved) CenturyLink, Inc.
Updates: 2308, 4033, 4034, 4035 (if CenturyLink, Inc.
approved) S. Bindinganaveli Raghavan
approved) Hughes Network Systems
Intended status: Standards Track D. Lawrence Hughes Network Systems
Expires: January 4, May 3, 2018 D. Lawrence
Akamai Technologies
July 3,
October 30, 2017

BULK DNS Resource Records
draft-woodworth-bulk-rr-06
draft-woodworth-bulk-rr-07

Abstract

The BULK DNS resource record type defines a method of pattern-based
creation of DNS resource records based on numeric substrings of query
names. The intent of BULK is to simplify generic assignments in a
memory-efficient way that can be easily shared between the primary
and secondary nameservers for a zone.

Ed note

Text inside square brackets ([]) is additional background
information, answers to frequently asked questions, general musings,
etc. They will be removed before publication. This document is
being collaborated on in GitHub at <https://github.com/vttale/bulk-
rr>. The most recent version of the document, open issues, etc
should all be available here. The authors gratefully accept pull
requests.

Status of This Memo

This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. https://datatracker.ietf.org/drafts/current/.

Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."

This Internet-Draft will expire on January 4, May 3, 2018.

This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info)
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.

Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Background and Terminology . . . . . . . . . . . . . . . 4
2. The BULK Resource Record . . . . . . . . . . . . . . . . . . 4
2.1. BULK RDATA Wire Format . . . . . . . . . . . . . . . . . 4
2.2. The BULK RR Presentation Format . . . . . . . . . . . . . 6
3. BULK Replacement . . . . . . . . . . . . . . . . . . . . . . 7
3.1. Matching the Domain Name Pattern . . . . . . . . . . . . 7
3.2. Record Generation using Replacement Pattern . . . . . . . 7
3.2.1. Delimiters . . . . . . . . . . . . . . . . . . . . . 8
3.2.2. Delimiter intervals . . . . . . . . . . . . . . . . . 8
3.2.3. Padding length . . . . . . . . . . . . . . . . . . . 8
3.2.4. Final processing . . . . . . . . . . . . . . . . . . 9
4. The NPN Resource Record . . . . . . . . . . . . . . . . . . . 9
4.1. NPN RDATA Wire Format . . . . . . . . . . . . . . . . . . 10
4.2. The NPN RR Presentation Format . . . . . . . . . . . . . 11
4.3. Use and Normalization Processing of NPN RRs . . . . . . . 11
4.3.1. Pseudocode for NPN Normalization Processing . . . . . 13
4.4. Pattern Based DNSSEC support . . . . . . . . . . . . . . 13
5. Known Limitations . . . . . . . . . . . . . . . . . . . . . . 13
5.1. 9
4.1. Unsupported Nameservers . . . . . . . . . . . . . . . . . 14
6. 9
5. Security Considerations . . . . . . . . . . . . . . . . . . . 14
6.1. 10
5.1. DNSSEC Signature Strategies . . . . . . . . . . . . . . . 14
6.1.1. 10
5.1.1. On-the-fly Signatures . . . . . . . . . . . . . . . . 14
6.1.2. Normalized (NPN-Based) Signatures 10
5.1.2. Alternative Signature Scheme . . . . . . . . . . 15
6.1.3. . . 10
5.1.3. Non-DNSSEC Zone Support Only . . . . . . . . . . . . 15
6.2. DNSSEC Validator Details . . . . . . . . . . . . . . . . 15
6.3. 11
5.2. DDOS Attack Vectors and Mitigation . . . . . . . . . . . 16
6.4. 11
5.3. Implications of Large-Scale DNS Records . . . . . . . . . 16
7. 11
6. Privacy Considerations . . . . . . . . . . . . . . . . . . . 16
8. 12
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
9. 12
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 17
10. 12
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 17
10.1. 12
9.1. Normative References . . . . . . . . . . . . . . . . . . 17
10.2. 12
9.2. Informative References . . . . . . . . . . . . . . . . . 18 13
Appendix A. BULK Examples . . . . . . . . . . . . . . . . . . . 18 13
A.1. Example 1 . . . . . . . . . . . . . . . . . . . . . . . . 18 13
A.2. Example 2 . . . . . . . . . . . . . . . . . . . . . . . . 19 14
A.3. Example 3 . . . . . . . . . . . . . . . . . . . . . . . . 19
Appendix B. NPN Examples . . . . . . . . . . . . . . . . . . . . 20
B.1. EXAMPLE 1 . . . . . . . . . . . . . . . . . . . . . . . . 20
B.2. EXAMPLE 2 . . . . . . . . . . . . . . . . . 15

Authors' Addresses . . . . . . . 21
B.3. EXAMPLE 3 . . . . . . . . . . . . . . . . . . . . . . . . 22
B.4. EXAMPLE 4 . . . . . . . . . . . . . . . . . . . . . . . . 22
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 24 15

1. Introduction

The BULK DNS resource record defines a pattern-based method for on-
the-fly resource record generation. It is essentially an enhanced
wildcard mechanism, constraining generated resource record owner
names to those that match a pattern of variable numeric substrings.
It is also akin to the $GENERATE master file directive [bind-arm]
without being limited to numeric values and without creating all
possible records in the zone data.

For example, consider the following record:

example.com. 86400 IN BULK A (
pool-A-[0-255]-[0-255].example.com.
10.55.${1}.${2}
)

It will answer requests for pool-A-0-0.example.com through pool-
A-255-255.example.com with the IPv4 addresses 10.55.0.0 through
10.55.255.255.

Much larger record sets can be defined while minimizing the
associated requirements for server memory and zone transfer network
bandwidth.

DNSSEC support is also described. The Numeric Pattern Normalization
(NPN) resource

This record provides addresses a way number of generating pattern-based
DNSSEC signatures, real-world operational problems
that authoritative DNS service providers experience. For example,
operators who host many large reverse lookup zones, even for only
IPv4 space in in-addr.arpa, would benefit from the disk space, memory
size, and securely performing DNSSEC validation zone transfer efficiencies that are gained by encapsulating
a simple record-generating algorithm versus enumerating all of the
individual records to cover the same space.

Production zones of tens of thousands of pattern-generated records
currently exist, that could be reduced to just one BULK RR. These
zones can look deceptively small on such
signatures. the primary nameserver and
balloon to 100MB or more when expanded,

BULK also allows administrators to more easily deal with singletons,
records in the pattern space that are an exception to the normal data
generation rules. Whereas a mechanism like $GENERATE may need to be
adjusted to account for these individual records, the processing
rules for BULK have explicit records more naturally override the
dynamically generated ones. This collision problem is not just a
theoretical concern, but a real source of support calls for
providers.

Pattern-generated records are also not only for the reverse DNS
space. Forward zones also occasionally have entries that follow
patterns that would be well-addressed by the BULK RR.

1.1. Background and Terminology

The reader is assumed to be familiar with the basic DNS and DNSSEC
concepts described in [RFC1034], [RFC1035], [RFC4033], [RFC4034], and
[RFC4035]; subsequent RFCs that update them in [RFC2181] and
[RFC2308]; and DNS terms in [RFC7719].

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in [RFC2119].
[RFC2119] when, and only when, they appear in all capitals, as shown
here.

2. The BULK Resource Record

The BULK resource record enables an authoritative nameserver to
generate RRs for other types based upon the query received.

The Type value for the BULK RR type is TBD.

The BULK RR is class-independent.

2.1. BULK RDATA Wire Format

The RDATA for a BULK RR is as follows:

1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Match Type | /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Domain Name Pattern /
/ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ /
/ Replacement Pattern /
/ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Match Type identifies the type of the RRset to be generated by this
BULK record. It is two octets corresponding to an RR TYPE code as
specified in [RFC1035], Section 3.2.1.

Domain Name Pattern consists of a pattern encoded as a wire-format
fully qualified domain name. The full name is used so that numeric
substrings above the zone cut can be captured in addition to those in
the zone. It needs no length indicator for the entire field because
the root label marks its end.

Special characters are interpreted as per the following Augmented
Backus-Naur Form (ABNF) notation from [RFC5234].

match = 1*(range / string)

range = "[" decnum [decnum "-" decnum decnum] "]" /
"<" hexnum [hexnum "-" hexnum hexnum] ">"
; create references for substitution
; limit of 32 references
; [] is syntactic sugar for 0-255
; <> is syntactic sugar for 00-ff

string = 1*(ctext / quoted-char)

decnum = 1*decdigit
; constrained to 65535 maximum.

hexnum = 1*hexdigit
; constrained to ffff maximum.

octet = %x00-FF

decdigit = %x30-39
; 0-9
hexdigit = decdigit / 0x41-0x46 / 0x61-66
; 0-9, A-F, a-f

ctext = <any octet excepting "\">

quoted-char = "\" octet
; to allow special characters as literals

[ Should [] and <> be allowed as short for [0-255] and <00-ff>? ]

Interpretation of the Domain Name Pattern is described in detail in
the "BULK Replacement" section.

The limit of 32 Note that quoted-char must be stored
in the wire format to preserve its semantics when the BULK RR is
interpreted by nameservers.

The limit of 32 references is meant to simplify implementation
details. It is largely but not entirely arbitrary, as it could
capture every individual character of the text representation of a
full IPv6 address.

Replacement Pattern describes how the answer RRset MUST be generated
for the matching query. It needs no length indicator because its end
can be derived from the RDATA length minus Match Type and Domain Name
Pattern lengths. It uses the following additional ABNF elements:

replace = 1*(reference / string)

reference = "$" "{" (positions / "*") [options] "}"

positions = (position / posrange) 0*("," (position / posrange))

posrange = position "-" position

position = 1*decnum

options = delimiter [interval [padding]]

delimiter = "|" 0*(ctext | quoted-char)
; "\|" to use "|" as delimiter
; "\\" to use "\" as delimiter

interval = "|" *2decdigit

padding = "|" *2decdigit

[ Is this the formatting complexity beyond simple ${1}, ${2}, etc, really
worth it? I definitely see how it could make for shorter replacement
patterns, but does it enhance their clarity and usability? usability, adding a
feature someone really wants? ]

The Replacement Pattern MUST end in a period the root label if it is intended
to represent a fully qualified domain name.

2.2. The BULK RR Presentation Format

Match Type is represented as an RR type mnemonic or with [RFC3597]'s
generic TYPE mechanism.

Domain Name Pattern is represented as a fully qualified domain name
as per [RFC1035] Section 5.1 rules for encoding whitespace and other
special characters.

Replacement Pattern is represented by the standard <character-string>
text rules for master files as per [RFC1035] section 5.1.

It is suggested that lines longer than 80 characters be wrapped with
parenthetical line continuation, per [RFC1035] Section 5.1, starting
after Match Type and ending after Replacement Pattern.

3. BULK Replacement

When an a BULK-aware authoritative nameserver receives a query for which
it does not have a matching name or a covering wildcard, it MUST then
look for BULK RRs at the zone apex, selecting all BULK RRs with a
Match Type that matches the query type and a Domain Name Pattern that
matches the query name. Note that query type ANY will select all
Match Types, and all query types match a CNAME or DNAME Match Type [ and
DNAME? ]. Type.
One or more answer RRs will be generated per the replacement rules
below. Examples are provided in an appendix.

By only triggering the BULK algorithm when the query name does not
exist, administrators are given the flexibility to explicitly
override the behaviour of specific names that would otherwise match
the BULK record's Domain Name Pattern. This is unlike BIND's
$GENERATE directive, which adds the generated RRs to any existing
names.

3.1. Matching the Domain Name Pattern

A query name matches the Domain Name Pattern if the characters that
appear outside the numeric ranges match exactly and those within
numeric ranges have values that fall within the range. Numeric
matches MUST be of the appropriate decimal or hexadecimal type as
specified by the delimiters in the pattern. For example, if a range
is given as [0-255], then FF does not match even though its value as
a hexadecimal number is within the range. Leading zeros in the
numeric part(s) of the qname MUST be ignored; for example,
001.example.com, 01.example.com and 1.example.com would all match
[].example.com.

When a query name matches a Domain Name Pattern, the value in each
numeric range is stored for use by the Replacement Pattern, with
reference numbers starting at 1 and counting from the left. For
example, matching the query name host-24-156 against
host-[0-255]-[0-255] assigns 24 to ${1} and 156 to ${2}.

3.2. Record Generation using Replacement Pattern

The Replacement Pattern generates the record data by replacing the
${...} references with data captured from the query name, and copying
all other characters literally.

The simplest form of reference uses only the reference number between
the braces, "{" and "}". The value of the reference is simply copied
directly from the matching position of the query name.

The next form of reference notation uses the asterisk, "*". With
${*}, all captured values in order of ascending position, delimited
by its default delimiter (described below), are placed in the answer.

Numeric range references, such as ${1-4}, replaces all values
captured by those references, in order, delimited by the default
delimiter described below. To reverse the order in which they are
copied, reverse the upper and lower values, such as ${4-1}. This is
useful for generating PTR records from query names in which the
address is encoded in network order.

Similar to range references, separating positions by commas creates
sets for replacement. For example, ${1,4} would be replaced by the
first and fourth captured values, delimited its default delimiter.
This notation may be combined with the numeric range form, such as
${3,2,1,8-4}.

3.2.1. Delimiters

A reference can specify a delimiter to use by following a vertical
bar, "|", with zero or more characters. Zero characters, such as in
${1-3|}, means no delimiter is used, while other characters up to an
unescaped vertical bar or closing brace are copied between position
values in the replacement. The default delimiter is the hyphen, "-".

3.2.2. Delimiter intervals

A second vertical bar in the reference options introduces a delimiter
interval. The default behavior of a multi-position reference is to
combine each captured value specified with a delimiter between each.
With a delimiter interval the delimiters are only added between every
Nth value. For example, ${*|-|4} adds a hyphen between every group
of four captured positions. This can be a handy feature in the IPv6
reverse namespace where every nibble is captured as a separate value
and generated hostnames include sets of 4 nibbles. An empty or 0
value for the delimiter interval MUST be interpreted as the default
value of 1.

3.2.3. Padding length

The fourth and final reference option determines the field width of
the copied value. Shorter values MUST be padded with leading zeroes
("0") and longer values MUST be truncated to the width.

The default behavior, and that of an explicit empty padding length,
is that the captured query name substring is copied exactly. A width
of zero "0" is a signal to "unpad", and any leading zeros MUST be
removed. [ Unnecessary complexity? ]
If a delimiter interval greater than 1 is used, captured values
between the intervals will be concatenated and the padding or
unpadding applied as a unit and not individually. An example of this
would be ${*||4|4} which would combine each range of 4 captured
values and pad or truncate them to a width of 4 characters.

[ If this is kept, the element/feature should probably be renamed
from "padding" since it is just as likely to truncate. ]

3.2.4. Final processing

The string that results from all replacements is converted to the
appropriate RDATA format for the record type. If the conversion
fails, the SERVFAIL rcode MUST be set on the response. response, representing a
misconfiguration that the server was unable to perform. [ The EDNS
extended-error code would be useful here. ]

The TTL of each RR generated by a BULK RR is the TTL of the
corresponding BULK record itself. [ BULK should probably have its
own TTL field because using that of the record itself feels like bad
design. On the other hand, if BULK is never meant to be queried for
directly and only appears in authoritative data, its own TTL is
pretty useless normally. ]

The class for the RRSet is the class of the BULK RR.

If the generated record type is one that uses domain names in its
resource record data, such as CNAME, a relative domain names MUST be
fully qualified with the origin domain of the BULK RR.

4. The NPN Resource Record

The Numeric Pattern Normalization (NPN) Known Limitations

This section defines known limitations of the BULK resource type.

4.1. Unsupported Nameservers

Authoritative nameservers that do not understand the semantics of the
new record provides pre-
processing information type will not be able to reduce deliver the number intended answers even
when the type appears in their zone data This significantly affects
the interoperability of possible variants primary versus secondary authorities that
can be generated by a BULK RR into one signable record. By
identifying parts of are
not all running the dynamic resource record same software. Adding new RRs which should be
ignored affect
handling by authoritative servers, or represented as a static value, one exemplar record and
signature is used being unable to validate all other records that match the
pattern.

For example, a pattern replacement like pool-A-${1}-${2}.example.com
that generates PTR records for pool-A-0-0.example.com through pool-
A-255-255.example.com would have add them, is an NPN record
issue that signals a
validating resolver needs to verify all pool-A-#-#.example.com names
against a record for pool-A-9-9.example.com.

Though it is imperfect in that forged records could be validated as
legitimate, it is nevertheless an improvement over the explored more thoroughly within dnsop.

5. Security Considerations

Two known security
afforded by non-DNSSEC DNS.

The Type value considerations exist for the NPN RR type is TBD.

The NPN RR is class independent BULK resource record,
DNSSEC and has no special TTL requirements.

4.1. NPN RDATA Wire Format

The RDATA DDOS attack vectors.

5.1. DNSSEC Signature Strategies

DNSSEC was designed to provide validation for an NPN RR consists DNS resource records,
requiring each tuple of a 2 octet Match Type field, a 1
octet Flags field, a 1 octet Owner Ignore field, a 1 octet Left
Ignore field owner, class, and a 1 octet Right Ignore field.

Match Type indicates the type to have its own
signature. This essentially defeats the purpose of providing large
generated blocks of RRs in a single RR as each generated RR would
require its own legitimate RRSIG record.

In the RRset with which following sections several options are discussed to address
this record is
associated.

Flags defines additional processing parameters for data
normalization. This document defines only issue. Of the Period-As-Number flag
"." (position 5), options, on-the-fly provides the Hyphen-As-Number "-" (position 6) most secure
solution and NPN provides the
hexadecimal flag "X" (position 7). All other flags are reserved for
future use.

0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|Reserved |.|-|X|
+-+-+-+-+-+-+-+-+

Bits 0-4: Reserved for future

Bit 5: Period As Number (.) Flag
If 0, periods are treated as non-digits.
If 1, periods will most flexible.

5.1.1. On-the-fly Signatures

A significant design goal of DNSSEC was to be processed able to do offline
cryptographic signing of zone contents, keeping the key material more
secure.

On-the-fly processing requires authoritative nameservers to sign
generated records as digits.

Bit 6: Hyphen As Number (-) Flag
If 0, hyphens they are treated as non-digits.
If 1, hyphens created. Not all authoritative
nameserver implementations offer on-the-fly signatures, and even with
those that do not all operators will be processed as digits.

Bit 7: Hexadecimal (X) Flag
If 0, numeric digits include only 0-9.
If 1, numeric digits include a-f in addition want to 0-9.

Owner Ignore defines the number of octets in the owner name, as
counted from the left, which MUST keep signing keys
online. This solution would either require all implementations to
support on-the-fly signing or be ignored by the normalization
process. This field offers additional security to pattern based
signatures implementations which may can
not be immediately apparent. By restricting the
leftmost characters defined by this value, ultimately the length of
the generated portion of the accompanying BULK RR or will be confined
accordingly.

Left Ignore defines not comply.

One possibly mitigation for addressing the number of octets risk of keeping the generated RDATA, as
counted from the left, which MUST zone
signing key online would be ignored by the normalization
process.

Right Ignore defines to continue to keep the number key for signing
positive answers offline and introduce a second key for online
signing of octets negative answers.

No changes to validating resolvers is required to support this
solution.

5.1.2. Alternative Signature Scheme

Previous versions of this draft proposed a new signature scheme using
a Numeric Pattern Normalization (NPN) RR. It was a method to support
offline signatures for BULK records, with the generated RDATA, as
counted drawback that is
required updates to DNSSEC-aware resolvers.

That mechanism is not specific to BULK and has been removed from the right, which MUST be ignored by the normalization
process.

4.2. The NPN RR Presentation Format

Match Type
current draft. If there is represented further interest in pursuing it, it can
be reopened as an RR type mnemonic or with [RFC3597]'s
generic TYPE mechanism.

Flags is a string of characters indicating the status separate draft.

5.1.3. Non-DNSSEC Zone Support Only

As a final option zones which wish to remain entirely without DNSSEC
support may serve such zones without either of each bit as
per the following table. The characters can appear in any order.

+------------------+-----------+-----------+
| Flag | Unset | Set |
+------------------+-----------+-----------+
| Period As Number | | . |
+------------------+-----------+-----------+
| Hyphen As Number | | - |
+------------------+-----------+-----------+
| Hexadecimal | 9 | f |
+------------------+-----------+-----------+

Owner Ignore, Left Ignore, and Right Ignore are displayed as unsigned
decimal integers, ranging from 0 through 255.

4.3. Use above solutions
and Normalization Processing of NPN records generated based on BULK RRs

[ This section needs reworking still, will require zero support
from recursive resolvers.

5.2. DDOS Attack Vectors and should perhaps Mitigation

As an additional defense against Distributed Denial Of Service (DDOS)
attacks against recursive (resolving) nameservers it is highly
recommended shorter TTLs be pulled
out into used for BULK RRs than others. While
disabling caching with a separate document. Notably one of issues that zero TTL is not
really described well is that, recommended, as designed so far, at signing time this would
only result in a shift of the NPN record has attack target, a balance will need to
be associated with the matching BULK record,
which is slightly problematic with regard found. While this document uses 24 hours (86400 seconds) in its
examples, values between 300 to the idea that NPNs 900 seconds are
suggested to be extended to be used in the future with other
patterns-based record generation. Once the likely more
appropriate BULK record and is selected, the signer would then have to understand its semantics
to fake up the exemplar to sign - raising the question as to why it
doesn't also know the RECOMMENDED. What is ultimately deemed
appropriate values for the Ignore fields, since
it will have may differ from zone to understand what the static zone and variable parts are.

One way around all this is administrator to just sign the BULK record itself
administrator.

[ I am unclear how this helps DDOS mitigation against anyone at all,
and
return it suspect this section should be removed.. ]

5.3. Implications of Large-Scale DNS Records

The production of such large-scale records in the additional section along with the answer, so that
the resolver wild may have some
unintended side-effects. These side-effects could validate not only a signature but the resulting
record based on the substitution algorithm. It'd still be
problematic for older DNSSEC validators that don't grok BULK, but no
more so than not grokking NPN. Unfortunately to them in both cases
the type-appropriate answer itself will be unsigned and thus fail
validation. ]

This document provides a minor yet significant modification to DNSSEC
regarding how RRsets will be signed or verified. Specifically the
Signature Field of [RFC4034], Section 3.1.8. Prior concern or
add unexpected complications to processing
into canonical form, signed zones may contain associated RRs where;
owner, class DNS based security offerings or
forensic and type anti-spam measures. While outside the scope of a non NPN RR directly corresponds with an
NPN RR matching owner, class and Match Type. If this condition
exists the NPN RR's RDATA defines details for processing the
associated RDATA into a "Normalized" format. Normalized data is
based
document, implementers of technology relying on pre-canonical formatting and zero padded for "A" and "AAAA"
RR types for acceptable precision during the process. This concept
will become clearer in the NPN pseudocode and examples provided in
the sections to follow.

The rules DNS resource records
for this transformation are simple:

o For RR's Owner field, characters from the beginning to critical decision making must take into consideration how the index
existence of the Owner Ignore value or the final string such a volume of characters
belonging records might impact their technology.

Solutions to the zone's ORIGIN MUST NOT be modified by this
algorithm. While the Owner Ignore value is not used magnitude problem for BULK
records but is included with the expectation other pattern-based
resource records may emerge and leverage NPN records for their
DNSSEC support requirements.

o For RR's RDATA field, character from beginning generated RRs are
expected be similar if not identical to the index of
Left Ignore value or characters with index that of Right Ignore value
to existing wildcard
records, the end MUST NOT be modified by this algorithm.

o In core difference being the remaining portion of both Owner and resultant RDATA strings will be unique
for each requested Domain Name within its scope.

The authors of
numeric data, defined as character "0" through "f" or "0" through
"9" depending on whether or not the Hexadecimal flag is set or
not, MUST be consolidated to a single character and set to the
highest value defined by the Hexadecimal flag. Examples may be
found in the following section. If period-as-number or hyphen-as-
number flags are set whichever this document are used ("." or "-") would be
treated as part of the number and consolidated where appropriate.

Once the normalization has been performed the signature will continue
processing into canonical form using confident that by careful
consideration, negative_side-effects produced by implementing the normalized RRs
features described in the place
of original ones.

NPN RRs MAY this document can be included in the "Additional" section to provide a hint
of the NPN processing required for the verification path.

It is important eliminated from any such
service or product.

6. Privacy Considerations

The BULK record does not introduce any new privacy concerns to note, properly sizing the Ignore fields DNS
data.

7. IANA Considerations

IANA is
critical requested to minimizing assign numbers for the risk of spoofed signatures. Never
intentionally set all Ignore values to zero in order to make
validation easier BULK RR.

8. Acknowledgments

This document was created as it places an extension to the validity of zone data at risk.
Only accompany RRs which are pattern derived (such as BULK) with NPN
records as doing so may unnecessarily reduce DNS infrastructure.
As such, many people over the confidence level of
generated signatures.

4.3.1. Pseudocode for NPN Normalization Processing

This section provides a simple demonstration of process flow for NPN
rdata normalization years have contributed to its creation
and DNSSEC signatures.

The pseudocode provided below assumes all associated RRs the authors are valid
members appreciative to each of a DNSSEC-compatible RRset, including BULK generated ones.

for rr in rrset them even if (has_NPN<rr.owner, rr.class, rr.type>)
rr.rdata_normal = NPN_normalize<rr.rdata>
add_to_sigrrset<NPN.owner, rr.class, rr.type,
rr.rdata_normal>
next
else
add_to_sigrrset<rr.owner, rr.class, rr.type, rr.rdata>
next

process_canonical_form<sigrrset>

dnssec_sign<sigrrset>

Similar logic MUST be used not thanked
or identified individually.

A special thanks is extended for determining DNSSEC validity the kindness, wisdom and technical
advice of RRsets
in validating nameservers for signatures generated based on NPN
normalization.

4.4. Pattern Based DNSSEC support

The NPN resource record could be used to support other dynamic RR
types which do not currently exist.

5. Known Limitations

This section defines known limitations of the BULK resource type.

5.1. Unsupported Nameservers

Authoritative nameservers that do not understand the semantics of the
new record type will not be able to deliver the intended answers even
when the type appears in their zone data This significantly affects
the interoperability of primary versus secondary authorities that are
not all running the same software. Adding new RRs which affect
handling by authoritative servers, or being unable to add them, is an
issue that needs to be explored more thoroughly within dnsop.

On the resolver side, rolling out a new semantics in DNSSEC has also
proven to be difficult in the past. Lacking NPN support effectively
means that operators using BULK will have to forego DNSSEC signing of
the affected zones, or do online signing of the dynamically generated
records.

6. Security Considerations

Two known security considerations exist for the BULK resource record,
DNSSEC and DDOS attack vectors.

6.1. DNSSEC Signature Strategies

DNSSEC was designed to provide validation for DNS resource records.
In a nutshell this requires each (owner, class, type) tuple to have
its own signature. This essentially defeats the purpose of providing
large generated blocks of RRs in a single RR as each generated RR
would require its own legitimate RRSIG record.

In the following sections several options are discussed to address
this issue. Of the options, on-the-fly provides the most secure
solution and NPN provides the most flexible.

6.1.1. On-the-fly Signatures

This solution requires authoritative nameservers to sign generated
records as they are created. Not all authoritative nameserver
implementations offer on-the-fly signatures, and even with those that
do not all operators will want to keep signing keys online, so this
solution would either require all implementations to support on-the-
fly signing or be ignored by implementations which can not or will
not comply.

No changes to validating resolvers is required to support this
solution.

6.1.2. Normalized (NPN-Based) Signatures

This solution provides the most flexible solution as nameservers
without on-the-fly signing capabilities can still support signatures
for BULK records. The down side to this solution is it requires
additional DNSSEC-aware resolver support.

It has been pointed out that due to this limitation, creation of
DNSSEC-signed BULK RRs requiring NPN support SHOULD be formally
discouraged until such time a respectable percentage (>80%) of
validating resolvers in-the-wild possess NPN processing capabilities.
Until that time, on-the-fly signing and unsigned records offer the
intended capabilities of the BULK specification, while requiring zero
new features to support RR resolution. The authors would like to
encourage opening this door for pattern based technologies such as
NPN records as a solution to BULK RRs as well as other pattern based
RRs to come. Given enough time, enough nameservers will be patched
and upgraded for unrelated reasons and by means of simple attrition
can supply a level of inertia and eventually widespread adoption can
be assumed.

NPN records are likely to be a topic of great debate as to their own
security limitations. It is, however, the authors' belief that while
any logic which limits the input of digital signatures lessens the
validity of those signatures, the limitation is minimal and the gain
is significant. The main reason for this is as a general rule, RRs
used in a generic manner such as conventional $GENERATE RRs or
scripted mass pattern generated RRs have a lesser importance than
other RRs in managed zones. These therefore inherently pose less
risk by means of attack and have a much less reward by defeating
security measures.

This being said, care must still be taken to set the Ignore fields
appropriately to minimize exposure and only use NPN RRs to secure
pattern-based records such as BULK.

6.1.3. Non-DNSSEC Zone Support Only

As a final option zones which wish to remain entirely without DNSSEC
support may serve such zones without either of the above solutions
and records generated based on BULK RRs will require zero support
from recursive (resolving) nameservers.

6.2. DNSSEC Validator Details

Verification of DNSSEC signed BULK generated RRs may be performed
against on-the-fly signatures with zero modification to their
behavior. However, verification using NPN records would require
changes to the logic to incorporate processing RDATA generated by
BULK logic as described above so the results will be compatible.

6.3. DDOS Attack Vectors and Mitigation

As an additional defense against Distributed Denial Of Service (DDOS)
attacks against recursive (resolving) nameservers it is highly
recommended shorter TTLs be used for BULK RRs than others. While
disabling caching with a zero TTL is not recommended, as this would
only result in a shift of the attack target, a balance will need to
be found. While this document uses 24 hours (86400 seconds) in its
examples, values between 300 to 900 seconds are likely more
appropriate and is RECOMMENDED. What is ultimately deemed
appropriate may differ from zone to zone and administrator to
administrator.

[ I am unclear how this helps DDOS mitigation against anyone at all.
]

6.4. Implications of Large-Scale DNS Records

The production of such large-scale records in the wild may have some
unintended side-effects. These side-effects could be of concern or
add unexpected complications to DNS based security offerings or
forensic and anti-spam measures. While outside the scope of this
document, implementers of technology relying on DNS resource records
for critical decision making must take into consideration how the
existence of such a volume of records might impact their technology.

Solutions to the magnitude problem for BULK generated RRs are
expected be similar if not identical to that of existing wildcard
records, the core difference being the resultant RDATA will be unique
for each requested Domain Name within its scope.

The authors of this document are confident that by careful
consideration, negative_side-effects produced by implementing the
features described in this document can be eliminated from any such
service or product.

7. Privacy Considerations

Neither the BULK nor NPN records introduce any new privacy concerns
to DNS data.

8. IANA Considerations

IANA is requested to assign numbers for two DNS resource record types
identified in this document: BULK and NPN.

9. Acknowledgments

This document was created as an extension to the DNS infrastructure.
As such, many people over the years have contributed to its creation
and the authors are appreciative to each of them even if not thanked
or identified individually.

A special thanks is extended for the kindness, wisdom and technical
advice of Robert Whelton (CenturyLink, Inc.) and Gary O'Brien
(Secure64).

10. References

10.1. Normative References

[RFC1034] Mockapetris, P., "Domain names - concepts and facilities",
STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,
<http://www.rfc-editor.org/info/rfc1034>.

[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,
November 1987, <http://www.rfc-editor.org/info/rfc1035>.

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.

[RFC2181] Elz, R. and R. Bush, "Clarifications to the DNS
Specification", RFC 2181, DOI 10.17487/RFC2181, July 1997,
<http://www.rfc-editor.org/info/rfc2181>.

[RFC2308] Andrews, M., "Negative Caching of DNS Queries (DNS
NCACHE)", RFC 2308, DOI 10.17487/RFC2308, March 1998,
<http://www.rfc-editor.org/info/rfc2308>.

[RFC2317] Eidnes, H., de Groot, G., and P. Vixie, "Classless IN-
ADDR.ARPA delegation", BCP 20, RFC 2317,
DOI 10.17487/RFC2317, March 1998,
<http://www.rfc-editor.org/info/rfc2317>.

[RFC3597] Gustafsson, A., "Handling of Unknown DNS Resource Record
(RR) Types", RFC 3597, DOI 10.17487/RFC3597, September
2003, <http://www.rfc-editor.org/info/rfc3597>.

[RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "DNS Security Introduction and Requirements",
RFC 4033, DOI 10.17487/RFC4033, March 2005,
<http://www.rfc-editor.org/info/rfc4033>.

[RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Resource Records for the DNS Security Extensions",
RFC 4034, DOI 10.17487/RFC4034, March 2005,
<http://www.rfc-editor.org/info/rfc4034>.

[RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Protocol Modifications for the DNS Security
Extensions", RFC 4035, DOI 10.17487/RFC4035, March 2005,
<http://www.rfc-editor.org/info/rfc4035>.

[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008,
<http://www.rfc-editor.org/info/rfc5234>.

10.2. Informative References

[bind-arm]
Internet Systems Consortium, "BIND 9 Configuration
Reference", 2016,
<https://ftp.isc.org/isc/bind9/cur/9.9/doc/arm/
Bv9ARM.html>.

[RFC7719] Hoffman, P., Sullivan, A., and K. Fujiwara, "DNS
Terminology", RFC 7719, DOI 10.17487/RFC7719, December
2015, <http://www.rfc-editor.org/info/rfc7719>.

Appendix A. BULK Examples

A.1. Example 1

$ORIGIN 2.10.in-addr.arpa.
@ 86400 IN BULK PTR (
[0-255].[0-255].[0-255].[0-255].in-addr.arpa.
pool-${4-1}.example.com.
)

A query received for the PTR of 4.3.2.10.in-addr.arpa will create the
references ${1} through ${4} with the first four labels of the query
name. The ${4-1} reference in the replacement pattern will then
substitute them in reverse with the default delimiter of hyphen
between every character and no special field width modifications.
The TTL of the BULK RR is used for the generated record, making the
response:

4.3.2.10.in-addr.arpa 86400 IN PTR pool-10-2-3-4.example.com.

A.2. Example 2

$ORIGIN 2.10.in-addr.arpa.
@ 86400 IN BULK PTR (
[0-255].[0-255].[0-255].[0-255].in-addr.arpa.
pool-${2,1|||3}.example.com.
)

Example 2 is similar to Example 1, except that it modifies the
replacement pattern. The empty option after the first vertical bar
causes no delimiters to be inserted, while the second empty option
that would keep the delimiter interval as 1. The latter is relevant
because the final value, padding of 3, is applied over each delimiter
interval even when no delimiter is used. Not all captures from the
substring are required to be used in the response.

The result is that a query for the PTR of 4.3.2.10.in-addr.arpa
generates this response:

4.3.2.10.in-addr.arpa 86400 IN PTR pool-003004.example.com.

[ Admittedly you can't do this very effectively without the field
width complexity. Is this sort of name common? Does it need
support? Admittedly $GENERATE had the feature, but is that reason
enough? ]

[ Change this to a hex matching example? ]

A.3. Example 3

This example contains a classless IPv4 delegation on the /22 CIDR
boundary as defined by [RFC2317]. The network for this example is
"10.2.0/22" delegated to a nameserver "ns1.sub.example.com.". RRs
for this example are defined as:

$ORIGIN 2.10.in-addr.arpa.
@ 7200 IN BULK CNAME [0-255].[0-3] ${*|.}.0-3
0-3 86400 IN NS ns1.sub.example.com.

A query for the PTR of 25.2.2.10.in-addr.arpa is received and the
BULK record with the CNAME Match Type matches all query types. 25
and 2 are captured as references, and joined in the answer by the
period (".") character as a delimiter, with ".0-3" then appended
literally and fully qualified by the origin domain. The final
synthesized record is:

25.2.2.10.in-addr.arpa 7200 IN CNAME 25.2.0-3.2.10.in-addr.arpa.

[ Without $* and options complexity, the pattern to get the same
result is just ${1}.{$2}.0-3 which is not really significantly
onerous to enter, and slightly less arcane looking to comprehend. ]

Appendix B. NPN Examples

B.1. EXAMPLE 1

2.10.in-addr.arpa. 86400 IN BULK PTR (
[0-255].[0-10].2.10.in-addr.arpa.
pool-A-${1}-${2}.example.com.
)
2.10.in-addr.arpa. 86400 IN NPN PTR 9 0 7 13

A query for the PTR of address 10.2.3.44 would match As shown
previously in BULK RR examples the query would match the BULK record
for the query name 44.3.2.10.in-addr.arpa, generating a PTR to pool-
A-3-44.example.com as the answer.

By protecting the "Ignore" characters from the generated RR's RDATA
the focus for normalization becomes "3-44" as illustrated below.

0 1 2 3 4 5 6 7
v---------
p o o l - A - 3 - 4 4 . e x a m p l e . c o m .
---------^
1 1 1 1
3 2 1 0 9 8 7 6 5 4 3 2 1 0

Everything to the left of "3-44" will remain intact, as will
everything to its right. The remaining characters will be processed
for digits between 0 and 9 as indicated by the NPN record's
hexadecimal flag 9, and each run of digits replaced by the single
character "9". The final Normalized RDATA for *.2.10.in-addr.arpa
would therefore become pool-A-9-9.example.com., and its signature
would be based on this value to cover all possible permutations of
the pool-A-${1}-${2}.example.com replacement pattern.

Since the validating nameserver would use the identical NPN record
for processing and comparison, all RRs generated by the BULK record
can now be verified with a single signature.

B.2. EXAMPLE 2

$ORIGIN 2.10.in-addr.arpa.
0-3 86400 IN NS ns1.sub.example.com.
86400 IN BULK CNAME [0-255].[0-3] ${*|.}.0-3
86400 IN NPN CNAME 9 0 0 23

For this example, a query of "10.2.2.65" would enter the nameserver
as "65.2.2.10.in-addr.arpa." Robert Whelton (CenturyLink, Inc.) and a "CNAME" RR with the RDATA of
"65.2.0-3.2.10.in-addr.arpa." would be generated.

By protecting the "Ignore" characters from the generated RR's RDATA
the focus for normalization becomes "65.2" as illustrated below.

0
v---------
6 5 . 2 . 0 Gary O'Brien
(Secure64 Software Corp).

9. References

9.1. Normative References

[RFC1034] Mockapetris, P., "Domain names - 3 . 2 . 1 0 . i n concepts and facilities",
STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,
<https://www.rfc-editor.org/info/rfc1034>.

[RFC1035] Mockapetris, P., "Domain names - a d d r . a r p a .
---------^
2 2 2 2 1 1 1 1 1 1 1 1 1 1
3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0

Everything implementation and
specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,
November 1987, <https://www.rfc-editor.org/info/rfc1035>.

[RFC2119] Bradner, S., "Key words for use in RFCs to the left of "65.2" will remain intact as will
everything Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.

[RFC2181] Elz, R. and R. Bush, "Clarifications to its right. The remaining characters will be processed
for digits from 0 through 9 as indicated by the NPN record's
hexadecimal flag "9", with each run replaced by the single character
"9". The final normalized RDATA would therefore become 9.9.0-
3.2.10.in-addr.arpa DNS
Specification", RFC 2181, DOI 10.17487/RFC2181, July 1997,
<https://www.rfc-editor.org/info/rfc2181>.

[RFC2308] Andrews, M., "Negative Caching of DNS Queries (DNS
NCACHE)", RFC 2308, DOI 10.17487/RFC2308, March 1998,
<https://www.rfc-editor.org/info/rfc2308>.

[RFC2317] Eidnes, H., de Groot, G., and P. Vixie, "Classless IN-
ADDR.ARPA delegation", BCP 20, RFC 2317,
DOI 10.17487/RFC2317, March 1998,
<https://www.rfc-editor.org/info/rfc2317>.

[RFC3597] Gustafsson, A., "Handling of Unknown DNS Resource Record
(RR) Types", RFC 3597, DOI 10.17487/RFC3597, September
2003, <https://www.rfc-editor.org/info/rfc3597>.

[RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and its signature would be based on this
normalized RDATA field. This new normalized string would be used as
an RDATA S.
Rose, "DNS Security Introduction and Requirements",
RFC 4033, DOI 10.17487/RFC4033, March 2005,
<https://www.rfc-editor.org/info/rfc4033>.

[RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Resource Records for the wildcard label of 2.10.in-addr.arpa now encompassing
all possible permutations of the ${*|.}.0-3.2.10.in-addr.arpa.
pattern.

As in example 1, the validatating resolver would use the same NPN
record for comparison.

B.3. EXAMPLE 3

This example provides reverse logic for example 1 by providing an
IPv4 address record DNS Security Extensions",
RFC 4034, DOI 10.17487/RFC4034, March 2005,
<https://www.rfc-editor.org/info/rfc4034>.

[RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Protocol Modifications for a requested hostname. For this example the
query is defined as an A record for pool-A-3-44.example.com, with an
origin of example.com. RRs DNS Security
Extensions", RFC 4035, DOI 10.17487/RFC4035, March 2005,
<https://www.rfc-editor.org/info/rfc4035>.

[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for this example are defined as:

example.com. 86400 IN BULK A (
pool-A-[0-10]-[0-255]
10.2.${*}
)
example.com. 86400 IN NPN A Syntax
Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008,
<https://www.rfc-editor.org/info/rfc5234>.

9.2. Informative References

[bind-arm]
Internet Systems Consortium, "BIND 9 0 8 0

By protecting the "Ignore" characters from the generated RR's RDATA
the focus for normalization becomes "003.044" as illustrated below.

0 1 2 3 4 5 6 7 8
v--------------
0 1 0 . 0 0 2 . 0 0 3 . 0 4 4
---------------^
0

This example illustrates a key point about NPN records; since they
are pre-canonical they MUST operate on a strict subset of WIRE
formatted data. For Configuration
Reference", 2016,
<https://ftp.isc.org/isc/bind9/cur/9.9/doc/arm/
Bv9ARM.html>.

[RFC7719] Hoffman, P., Sullivan, A., and K. Fujiwara, "DNS
Terminology", RFC 7719, DOI 10.17487/RFC7719, December
2015, <https://www.rfc-editor.org/info/rfc7719>.

Appendix A. BULK Examples

A.1. Example 1
$ORIGIN 2.10.in-addr.arpa.
@ 86400 IN BULK PTR (
[0-255].[0-255].[0-255].[0-255].in-addr.arpa.
pool-${4-1}.example.com.
)

A and AAAA records this means the "Ignore"
fields are based on zero padded data. In this example our generated
record MUST be converted into "010.002.003.044" (shown above) prior
to processing. After processing, wire format would become
"0x0A02032C" (shown in hexadecimal). This format would be too
imprecise query received for normalization so padded decimal is used.

Everything to the left PTR of "003.044" will remain intact as 4.3.2.10.in-addr.arpa will
everything to its right. create the
references ${1} through ${4} with the first four labels of the query
name. The remaining characters ${4-1} reference in the replacement pattern will be processed
for digits then
substitute them in reverse with the default delimiter of hyphen
between 0 every character and 9 as indicated by no special field width modifications.
The TTL of the NPN record's
hexadecimal flag "9" and each run replaced by BULK RR is used for the single character
"9". generated record, making the
response:

4.3.2.10.in-addr.arpa 86400 IN PTR pool-10-2-3-4.example.com.

A.2. Example 2

$ORIGIN 2.10.in-addr.arpa.
@ 86400 IN BULK PTR (
[0-255].[0-255].[0-255].[0-255].in-addr.arpa.
pool-${2,1|||3}.example.com.
)

Example 2 is similar to Example 1, except that it modifies the
replacement pattern. The final Normalized RDATA would therefore become 10.2.9.9 and
its signature would empty option after the first vertical bar
causes no delimiters to be based on this normalized RDATA field. This
new normalized A RR inserted, while the second empty option
that would be used keep the delimiter interval as an RDATA for 1. The latter is relevant
because the wildcard label final value, padding of "*.example.com." now encompassing 3, is applied over each delimiter
interval even when no delimiter is used. Not all possible permutations of captures from the
10.2.${*} pattern.

B.4. EXAMPLE 4

This example provides similar logic for an IPv6 AAAA record. For
this example
substring are required to be used in the response.

The result is that a query is defined as an AAAA record for pool-A-ff-
aa.example.com with an origin the PTR of example.com.. RRs for 4.3.2.10.in-addr.arpa
generates this example
are defined as:

example.com. 86400 IN BULK AAAA (
pool-A-[0-ffff]-[0-ffff]
fc00::${1}:${2}
)
example.com. response:

4.3.2.10.in-addr.arpa 86400 IN NPN AAAA X 0 30 0

By protecting the "Ignore" characters from the generated RR's RDATA
the focus for normalization becomes "00ff:00aa" as illustrated below.

1 1 1 1 1 1 1 1 1 1 2 2
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

f c 0 0 : 0 0 0 0 : 0 0 0 0 : 0 0 0 0 : -/-/

4 3 3 3 3 3 3 3 3 3 3 2 2 2 2 2 2 2 2 2 2 1
0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9
/-/-/- . . . . . . . . . . . . . . . . . . . . . . . . -/-/-/
2 2 2 2 2 2 2 2 2 3 3 3 3 3 3 3 3 3 3 4
1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
v------------------
/-/- 0 0 0 0 : 0 0 0 0 : 0 0 f f : 0 0 a a
-------------------^
2 1 1 1 1 1 1 1 1 1 1
0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0

This example reinforces PTR pool-003004.example.com.

[ Admittedly you can't do this very effectively without the point on pre-canonical processing of NPN
records; they MUST operate on a strict subset of WIRE formatted data.
For A and AAAA records field
width complexity. Is this means sort of name common? Does it need
support? Admittedly $GENERATE had the "Ignore" fields are based on
zero padded data. In feature, but is that reason
enough? ]

[ Change this example our generated record MUST be
converted into "fc00:0000:0000:0000:0000:0000:00ff:00aa" (shown
above) prior to processing. After processing, wire format would
become "0xFC000000000000000000000000FF00AA" (shown in hexadecimal). to a hex matching example? ]

A.3. Example 3

This format is slightly misleading example contains a classless IPv4 delegation on the /22 CIDR
boundary as it is truly only 16 bytes of
WIRE data and would be too imprecise defined by [RFC2317]. The network for normalization so padded
hexadecimal this example is used.

Everything
"10.2.0/22" delegated to a nameserver "ns1.sub.example.com.". RRs
for this example are defined as:

$ORIGIN 2.10.in-addr.arpa.
@ 7200 IN BULK CNAME [0-255].[0-3] ${*|.}.0-3
0-3 86400 IN NS ns1.sub.example.com.

A query for the left PTR of "00ff:00aa" will remain intact as will
everything to its right. The remaining characters will be processed
for numbers between "0" 25.2.2.10.in-addr.arpa is received and the
BULK record with the CNAME Match Type matches all query types. 25
and "f" 2 are captured as indicated references, and joined in the answer by the NPN record's
hexadecimal flag "X"
period (".") character as a delimiter, with ".0-3" then appended
literally and each run replaced fully qualified by the single character
"f". origin domain. The final Normalized RDATA would therefore become "fc00::f:f"
synthesized record is:

25.2.2.10.in-addr.arpa 7200 IN CNAME 25.2.0-3.2.10.in-addr.arpa.

[ Without $* and its signature would be based on this "normalized" RDATA field.
This new "normalized" "AAAA" RR would be used as an RDATA for options complexity, the
wildcard label of *.example.com now encompassing all possible
permutations of pattern to get the "fc00::${1}:${2}" pattern. same
result is just ${1}.{$2}.0-3 which is not really significantly
onerous to enter, and slightly less arcane looking to comprehend. ]

Authors' Addresses

John Woodworth
CenturyLink, Inc.
4250 N Fairfax Dr
Arlington VA 22203
USA

Email: John.Woodworth@CenturyLink.com

Dean Ballew
CenturyLink, Inc.
2355 Dulles Corner Blvd, Ste 200 300
Herndon VA 20171
USA

Email: Dean.Ballew@CenturyLink.com
Shashwath Bindinganaveli Raghavan
Hughes Network Systems
11717 Exploration Lane
Germantown MD 20876
USA

Email: shashwath.bindinganaveliraghavan@hughes.com

David C Lawrence
Akamai Technologies
150 Broadway
Cambridge MA 02142-1054
USA

Email: tale@akamai.com