| Internet Engineering Task Force | D. Wessels |
| Internet-Draft | P. Barber |
| Intended status: Experimental | M. Weinberg |
| Expires: April 25, 2019 | Verisign |
| W. Kumari | |
| W. Hardaker | |
| USC/ISI | |
| October 22, 2018 |
Message Digest for DNS Zones
draft-wessels-dns-zone-digest-04
This document describes an experimental protocol and new DNS Resource Record that can be used to provide an message digest over DNS zone data. The ZONEMD Resource Record conveys the message digest data in the zone itself. When a zone publisher includes an ZONEMD record, recipients can verify the zone contents for accuracy and completeness. This provides assurance that received zone data matches published data, regardless of how the zone data has been transmitted and received.
ZONEMD is not designed to replace DNSSEC. Whereas DNSSEC is designed to protect recursive name servers and their caches, ZONEMD protects applications that consume zone files, whether they be authoritative name servers, recursive name servers, or uses of zone file data.
As specified at this time, ZONEMD is not designed for use in large, dynamic zones due to the time and resources required for digest calculation. The ZONEMD record described in this document includes fields reserved for future work to support large, dynamic zones.
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 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 April 25, 2019.
Copyright (c) 2018 IETF Trust and the persons identified as the document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (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.
In the DNS, a zone is the collection of authoritative resource records (RRs) sharing a common origin ([RFC7719]). Zones are often stored as files on disk in the so-called master file format [RFC1034]. Zones are generally distributed between name servers using the AXFR [RFC5936], and IXFR [RFC1995] protocols. Zone files can also be distributed outside of the DNS, with such protocols as FTP, HTTP, rsync, and even via email. Currently there is no standard way to verify the authenticity of a stand-alone zone file.
This document introduces a new RR type that serves as a cryptographic message digest of the data in a zone file. It allows a receiver of the zone file to verify the zone file's authenticity, especially when used in combination with DNSSEC. This technique makes the message digest a part of the zone file itself, allowing verification the zone file as a whole, no matter how it is transmitted. Furthermore, the digest is based on the wire format of zone data. Thus, it independent of presentation format, such as changes in whitespace, capitalization, and comments.
DNSSEC provides three strong security guarantees relevant to this protocol:
This specification is OPTIONAL to implement by both publishers and consumers of zone file data.
The motivation for this protocol enhancement is the desire for the ability to verify the authenticity of a stand-alone zone file, regardless of how it is transmitted. A consumer of zone file data should be able to verify that the data is as-published by the zone operator.
One approach to preventing data tampering and corruption is to secure the distribution channel. The DNS has a number of features that can already be used for channel security. Perhaps the most widely used is DNS transaction signatures (TSIG [RFC2845]). TSIG uses shared secret keys and a message digest to protect individual query and response messages. It is generally used to authenticate and validate UPDATE [RFC2136], AXFR [RFC5936], and IXFR [RFC1995] messages.
DNS Request and Transaction Signatures (SIG(0) [RFC2931]) is another protocol extension designed to authenticate individual DNS transactions. Whereas SIG records were originally designed to cover specific RR types, SIG(0) is used to sign an entire DNS message. Unlike TSIG, SIG(0) uses public key cryptography rather than shared secrets.
The Transport Layer Security protocol suite is also designed to provide channel security. It is entirely possible, for example, to perform zone transfers using DNS-over-TLS ([RFC7858]). Furthermore, one can easily imagine the distribution of zone files over HTTPS-enabled web servers, as well as DNS-over-HTTPS [dns-over-https].
Unfortunately, the protections provided by these channel security techniques are ephemeral and are not retained after the data transfer is complete. They can ensure that the client receives the data from the expected server, and that the data sent by the server is not modified during transmission. However, they do not guarantee that the server transmits the data as originally published, and do not provide any methods to verify data that is read after transmission is complete. For example, a name server loading saved zone data upon restart cannot guarantee that the on-disk data has not been modified. For these reasons, it is preferable to secure the data itself.
Why not simply rely on DNSSEC, which provides certain data security guarantees? Certainly for zones that are signed, a recipient could validate all of the signed RRsets. Additionally, denial-of-existence records can prove that RRsets have not been added or removed. However, not all RRsets in a zone are signed. The design of DNSSEC stipulates that delegations (non-apex NS records) are not signed, and neither are any glue records. Thus, changes to delegation and glue records cannot be detected by DNSSEC alone. Furthermore, zones that employ NSEC3 with opt-out are susceptible to the removal or addition of names between the signed nodes. Whereas DNSSEC is primarily designed to protect consumers of DNS response messages, this protocol is designed to protect consumers of zone files.
There are existing tools and protocols that provide data security, such as OpenPGP [RFC4880] and S/MIME [RFC3851]. In fact, the internic.net site publishes PGP signatures along side the root zone and other files available there. However, this is a detached signature with no strong association to the corresponding zone file other than its timestamp. Non-detached signatures are, of course, possible, but these necessarily change the format of the file being distributed. That is, a zone file signed with OpenPGP or S/MIME no longer looks like a zone file and could not directly be loaded into a name server. Once loaded the signature data is lost, so it does not survive further propagation.
It seems the desire for data security in DNS zones was envisioned as far back as 1997. [RFC2065] is an obsoleted specification of the first generation DNSSEC Security Extensions. It describes a zone transfer signature, aka AXFR SIG, which is similar to the technique proposed by this document. That is, it proposes ordering all (signed) RRsets in a zone, hashing their contents, and then signing the zone hash. The AXFR SIG is described only for use during zone transfers. It did not postulate the need to validate zone data distributed outside of the DNS. Furthermore, its successor, [RFC2535], omits the AXFR SIG, while at the same time introducing an IXFR SIG.
This document introduces a new Resource Record type designed to convey a message digest of the content of a zone file. The digest is calculated at the time of zone publication. Ideally the zone is signed with DNSSEC to guarantee that any modifications of the digest can be detected. The procedures for digest calculation and DNSSEC signing are similar (i.e., both require the same ordering of RRs) and can be done in parallel.
The zone digest is designed to be used on zones that are relatively stable and have infrequent updates. As currently specified, the digest is re-calculated over the entire zone content each time. This specification does not provide an efficient mechanism for incremental updates of zone data. It does, however, reserve a field in the ZONEMD record for future work to support incremental zone digest algorithms (e.g. using Merkle trees).
It is expected that verification of a zone digest would be implemented in name server software. That is, a name server can verify the zone data it was given and refuse to serve a zone which fails verification. For signed zones, the name server needs a trust anchor to perform DNSSEC validation. For signed non-root zones, the name server may need to send queries to validate a chain-of-trust. Digest verification could also be performed externally.
The root zone [InterNIC] is perhaps the most widely distributed DNS zone on the Internet, served by 930 separate instances [RootServers] at the time of this writing. Additionally, many organizations configure their own name servers to serve the root zone locally. Reasons for doing so include privacy and reduced access time. [RFC7706] describes one, but not the only, way to do this. As the root zone spreads beyond its traditional deployment boundaries, the need for verification of the completeness of the zone contents becomes increasingly important.
Since its very early days, the developers of the DNS recognized the importance of secondary name servers and service diversity. However, they may not have anticipated the complexity of modern DNS service provisioning which can include multiple third-party providers and hundreds of anycast instances. Instead of a simple primary-to-secondary zone distribution system, today it is possible to have multiple levels, multiple parties, and multiple protocols involved in the distribution of zone data. This complexity introduces new places for problems to arise. The zone digest protects the integrity of data that flows through such systems.
DNS Response Policy Zones is "a method of expressing DNS response policy information inside specially constructed DNS zones..." [RPZ]. A number of companies provide RPZ feeds, which can be consumed by name server and firewall products. Since these are zone files, AXFR is often, but not necessarily used for transmission. While RPZ zones can certainly be signed with DNSSEC, the data is not queried directly, and would not be subject to DNSSEC validation.
ICANN operates the Centralized Zone Data Service [CZDS], which is a repository of top-level domain zone files. Users request access to the system, and to individual zones, and are then able to download zone data for certain uses. Adding a zone digest to these would provide CZDS users with assurances that the data has not been modified. Note that ZONEMD could be added to CZDS zone data independently of the zone served by production name servers.
Since the zone digest does not depend on presentation format, it could be used to compare multiple copies of a zone received from different sources, or copies generated by different processes.
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 BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.
This section describes the ZONEMD Resource Record, including its fields, wire format, and presentation format. The Type value for the ZONEMD RR is TBD. The ZONEMD RR is class independent. The RDATA of the resource record consists of three fields: Serial, Digest Type, and Digest.
FOR DISCUSSION: This document is currently written as though a zone MUST NOT contain more than one ZONEMD RR. Having exactly one ZONEMD record per zone simplifies this protocol and eliminates confusion around downgrade attacks, at the expense of algorithm agility.
The ZONEMD RDATA wire format is encoded 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Serial |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Digest Type | Reserved | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| Digest |
/ /
/ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Serial field is a 32-bit unsigned integer in network order. It is equal to the serial number from the zone's SOA record ([RFC1035] section 3.3.13) for which the message digest was generated.
The Digest Type field is an 8-bit unsigned integer, with meaning equivalent to the Digest Type of the DS resource record, as defined in section 5.1.3 of [RFC4034] and values found in the IANA protocol registry for DS digest types [iana-ds-digest-types].
The status of ZONEMD digest types (e.g., mandatory, optional, deprecated), however, are independent of those for DS digest types.
At the time of this writing the following digest types are defined:
| Value | Description | Status | Reference |
|---|---|---|---|
| 1 | SHA1 | Deprecated | [RFC3658] |
| 2 | SHA256 | Mandatory | [RFC4509] |
| 3 | GOST R 34.11-94 | Deprecated | [RFC5933] |
| 4 | SHA384 | Optional | [RFC6605] |
The Reserved field is an 8-bit unsigned integer, which is always set to zero. This field is reserved for future work to support efficient incremental updates.
The Digest field is a variable-length sequence of octets containing the message digest. Section 3 describes how to calculate the digest for a zone. Section 4 describes how to use the digest to verify the contents of a zone.
The presentation format of the RDATA portion is as follows:
The Serial field MUST be represented as an unsigned decimal integer.
The Reserved field MUST be represented as an unsigned decimal integer set to zero.
The Digest Type field MUST be represented as an unsigned decimal integer.
The Digest MUST be represented as a sequence of case-insensitive hexadecimal digits. Whitespace is allowed within the hexadecimal text.
The following example shows a ZONEMD RR.
example.com. 86400 IN ZONEMD 2018031500 4 0 (
FEBE3D4CE2EC2FFA4BA99D46CD69D6D29711E55217057BEE
7EB1A7B641A47BA7FED2DD5B97AE499FAFA4F22C6BD647DE )
Calculation of the zone digest REQUIRES the RRs in a zone to be processed in a consistent format and ordering. Correct ordering of the zone depends on (1) ordering of owner names in the zone, (2) ordering of RRsets with the same owner name, and (3) ordering of RRs within an RRset.
This specification adopts DNSSEC's canonical ordering for names (Section 6.1 of [RFC4034]), and canonical ordering for RRs within an RRset (Section 6.3 of [RFC4034]). It also adopts DNSSEC's canonical RR form (Section 6.2 of [RFC4034]). However, since DNSSEC does not define a canonical ordering for RRsets having the same owner name, that ordering is defined here.
For the purposes of calculating the zone digest, RRsets having the same owner name MUST be numerically ordered by their numeric RR TYPE.
When AXFR is used to transfer zone data, the first and last records are always the SOA RR ([RFC5936] Section 2.2). Because of this, zone files on disk often contain two SOA RRs. When calculating the zone digest, the first SOA RR MUST be included and any subsequent SOA RRs MUST NOT be included.
Additionally, per established practices, the SOA record is generally the first record in a zone file. However, according to the requirement to sort RRsets with the same owner name by type, the SOA RR (type value 6) will not be first in the digest calculation. The zone's NS RRset (type value 2) at the apex MUST be processed before the SOA RR.
In preparation for calculating the zone digest, any existing ZONEMD record at the zone apex MUST first be deleted.
FOR DISCUSSION: Should non-apex ZONEMD records be allowed in a zone? Or forbidden?
Prior to calculation of the digest, and prior to signing with DNSSEC, a placeholder ZONEMD record MUST be added to the zone apex. This serves two purposes: (1) it allows the digest to cover the Serial, Reserved, and Digest Type field values, and (2) ensures that appropriate denial-of-existence (NSEC, NSEC3) records are created if the zone is signed with DNSSEC.
It is RECOMMENDED that the TTL of the ZONEMD record match the TTL of the SOA.
In the placeholder record, the Serial field MUST be set to the current SOA Serial. The Digest Type field MUST be set to the value for the chosen digest algorithm. The Digest field MUST be set to all zeroes and of length appropriate for the chosen digest algorithm.
Following addition of the placeholder record, the zone MAY be signed with DNSSEC. Note that when the digest calculation is complete, and the ZONEMD record is updated, the signature(s) for that record MUST be recalculated and updated as well. Therefore, the signer is not required to calculate a signature over the placeholder record at this step in the process, but it is harmless to do so.
The zone digest is calculated by concatenating the canonical on-the-wire form (without name compression) of all RRs in the zone, in the order described above, subject to the inclusion/exclusion rules described below, and then applying the digest algorithm:
digest = digest_algorithm( RR(1) | RR(2) | RR(3) | ... )
where "|" denotes concatenation, and
RR(i) = owner | type | class | TTL | RDATA length | RDATA
When calculating the digest, the following inclusion/exclusion rules apply:
FOR DISCUSSION: How should the protocol handle occluded data? A DNAME/NS record can occlude existing data, technically making it out-of-zone. However, BIND (and others) will load and AXFR such occluded data.
Once the zone digest has been calculated, its value is then copied to the Digest field of the ZONEMD record.
If the zone is signed with DNSSEC, the appropriate RRSIG records covering the ZONEMD record MUST then be added or updated. Because the ZONEMD placeholder was added prior to signing, the zone will already have the appropriate denial-of-existence (NSEC, NSEC3) records.
Some implementations of incremental DNSSEC signing might update the zone's serial number for each resigning. However, to preserve the calculated digest, generation of the ZONEMD signature at this time MUST NOT also result in a change of the SOA serial number.
The recipient of a zone that has a message digest record can verify the zone by calculating the digest as follows:
This memo is published as an Experimental RFC. The purpose of the experimental period is to provide the community time to analyze and evaluate to the methods defined in this document, particularly with regard to the wide variety of DNS zones in use on the Internet.
Additionally, the ZONEMD record defined in this document includes a Reserved field. The authors have a particular future use in mind for this field, namely to support efficient digests in large, dynamic zones. We intend to conduct future experiments using Merkle trees of varying depth. The choice of tree depth can be encoded in this reserved field.
FOR DISCUSSION: The authors are willing to remove the Reserved field from this specification if the working group would prefer it. It would mean, however, that a future version of this protocol designed to efficiently support large, dynamic zones would most likely require a new RR type.
The duration of the experiment is expected to be no less than two years from the publication of this document. If the experiment is successful, it is expected that the findings of the experiment will result in an updated document for Standards Track approval.
This document uses a new DNS RR type, ZONEMD, whose value TBD has been allocated by IANA from the "Resource Record (RR) TYPEs" subregistry of the "Domain Name System (DNS) Parameters" registry.
The ZONEMD Digest Type field has the same values as the DS RR Digest Type field, but with independent implementation status. Therefore, this document expects IANA will create a new "ZONEMD Digest Types" registry.
The zone digest allows the receiver to verify that the zone contents haven't been modified since the zone was generated/published. Verification is strongest when the zone is also signed with DNSSEC. An attacker, whose goal is to modify zone content before it is used by the victim, may consider a number of different approaches.
The attacker might perform a downgrade attack to an unsigned zone. This is why Section 4 RECOMMENDS that the verifier determine whether or not to expect DNSSEC signatures for the zone in step 1.
The attacker might perform a downgrade attack by removing the ZONEMD record. This is why Section 4 REQUIRES that the verifier checks DNSSEC denial-of-existence proofs in step 2.
The attacker might alter the Digest Type or Digest fields of the ZONEMD record. Such modifications are detectable only with DNSSEC validation.
Nothing in this specification prevents clients from making, and servers from responding to, ZONEMD queries. One might consider how well ZONEMD responses could be used in a distributed denial-of-service amplification attack.
The ZONEMD RR is moderately sized, much like the DS RR. A single ZONEMD RR contributes approximately 40 to 65 octets to a DNS response, for currently defined digest types. Certainly other query types result in larger amplification effects (i.e., DNSKEY).
This specification has no impacts on user privacy.
The authors wish to thank David Blacka, Scott Hollenbeck, and Rick Wilhelm for providing feedback on early drafts of this document. Additionally, they thank Joe Abley, Mark Andrews, Olafur Gudmundsson, Paul Hoffman, Evan Hunt, Shumon Huque, Tatuya Jinmei, Burt Kaliski, Shane Kerr, Matt Larson, John Levine, Ed Lewis, Mukund Sivaraman, Petr Spacek, Ondrej Sury, Florian Weimer, Tim Wicinksi, Paul Wouters, and other members of the dnsop working group for their input.
The authors have an open source implementation in C, using the ldns library [ldns-zone-digest]. This implementation is able to perform the following functions:
This implementation does not:
Shane Kerr wrote an implementation of this specification during the IETF 102 hackathon [ZoneDigestHackathon]. This implementation is in Python and is able to perform the following functions:
This implementation does not:
RFC Editor: Please remove this section.
This section lists substantial changes to the document as it is being worked on.
From -00 to -01:
From -01 to -02:
From -02 to -03:
From -03 to -04:
This appendex contains example zone files with accurate ZONEMD records. These can be used to verify an implementation of the zone digest protocol.
Here, the EXAMPLE zone contains an SOA record, NS and glue records, and a ZONEMD record for digest type 2 (SHA256).
example. 86400 IN SOA ns1 admin 2018031900 (
1800 900 604800 86400 )
86400 IN NS ns1
86400 IN NS ns2
86400 IN ZONEMD 2018031900 2 0 (
2d1dc6806312e79b
a86e64bad290e1c1
61f4ee8cb9d490e9
5a00d1e686b12826 )
ns1 3600 IN A 127.0.0.1
ns2 3600 IN AAAA ::1
The URI.ARPA zone retreived 2018-10-21.
; <<>> DiG 9.9.4 <<>> @lax.xfr.dns.icann.org uri.arpa axfr
; (2 servers found)
;; global options: +cmd
uri.arpa. 3600 IN SOA sns.dns.icann.org. (
noc.dns.icann.org. 2018100702 10800 3600 1209600 3600 )
uri.arpa. 3600 IN RRSIG NSEC 8 2 3600 (
20181028142623 20181007205525 47155 uri.arpa.
eEC4w/oXLR1Epwgv4MBiDtSBsXhqrJVvJWUpbX8XpetAvD35bxwNCUTi
/pAJVUXefegWeiriD2rkTgCBCMmn7YQIm3gdR+HjY/+o3BXNQnz97f+e
HAE9EDDzoNVfL1PyV/2fde9tDeUuAGVVwmD399NGq9jWYMRpyri2kysr q/g= )
uri.arpa. 86400 IN RRSIG NS 8 2 86400 (
20181028172020 20181007175821 47155 uri.arpa.
ATyV2A2A8ZoggC+68u4GuP5MOUuR+2rr3eWOkEU55zAHld/7FiBxl4ln
4byJYy7NudUwlMOEXajqFZE7DVl8PpcvrP3HeeGaVzKqaWj+aus0jbKF
Bsvs2b1qDZemBfkz/IfAhUTJKnto0vSUicJKfItu0GjyYNJCz2CqEuGD Wxc= )
uri.arpa. 600 IN RRSIG MX 8 2 600 (
20181028170556 20181007175821 47155 uri.arpa.
e7/r3KXDohX1lyVavetFFObp8fB8aXT76HnN9KCQDxSnSghNM83UQV0t
lTtD8JVeN1mCvcNFZpagwIgB7XhTtm6Beur/m5ES+4uSnVeS6Q66HBZK
A3mR95IpevuVIZvvJ+GcCAQpBo6KRODYvJ/c/ZG6sfYWkZ7qg/Em5/+3 4UI= )
uri.arpa. 3600 IN RRSIG DNSKEY 8 2 3600 (
20181028152832 20181007175821 15796 uri.arpa.
nzpbnh0OqsgBBP8St28pLvPEQ3wZAUdEBuUwil+rtjjWlYYiqjPxZ286
XF4Rq1usfV5x71jZz5IqswOaQgia91ylodFpLuXD6FTGs2nXGhNKkg1V
chHgtwj70mXU72GefVgo8TxrFYzxuEFP5ZTP92t97FVWVVyyFd86sbbR
6DZj3uA2wEvqBVLECgJLrMQ9Yy7MueJl3UA4h4E6zO2JY9Yp0W9woq0B
dqkkwYTwzogyYffPmGAJG91RJ2h6cHtFjEZe2MnaY2glqniZ0WT9vXXd
uFPm0KD9U77Ac+ZtctAF9tsZwSdAoL365E2L1usZbA+K0BnPPqGFJRJk
5R0A1w== )
uri.arpa. 3600 IN RRSIG DNSKEY 8 2 3600 (
20181028152832 20181007175821 55480 uri.arpa.
lWtQV/5szQjkXmbcD47/+rOW8kJPksRFHlzxxmzt906+DBYyfrH6uq5X
nHvrUlQO6M12uhqDeL+bDFVgqSpNy+42/OaZvaK3J8EzPZVBHPJykKMV
63T83aAiJrAyHzOaEdmzLCpalqcEE2ImzlLHSafManRfJL8Yuv+JDZFj
2WDWfEcUuwkmIZWX11zxp+DxwzyUlRl7x4+ok5iKZWIg5UnBAf6B8T75
WnXzlhCw3F2pXI0a5LYg71L3Tp/xhjN6Yy9jGlIRf5BjB59X2zra3a2R
PkI09SSnuEwHyF1mDaV5BmQrLGRnCjvwXA7ho2m+vv4SP5dUdXf+GTeA
1HeBfw== )
uri.arpa. 3600 IN RRSIG SOA 8 2 3600 (
20181029114753 20181008222815 47155 uri.arpa.
qn8yBNoHDjGdT79U2Wu9IIahoS0YPOgYP8lG+qwPcrZ1BwGiHywuoUa2
Mx6BWZlg+HDyaxj2iOmox+IIqoUHhXUbO7IUkJFlgrOKCgAR2twDHrXu
9BUQHy9SoV16wYm3kBTEPyxW5FFm8vcdnKAF7sxSY8BbaYNpRIEjDx4A JUc= )
uri.arpa. 3600 IN NSEC ftp.uri.arpa. NS SOA (
MX RRSIG NSEC DNSKEY )
uri.arpa. 86400 IN NS a.iana-servers.net.
uri.arpa. 86400 IN NS b.iana-servers.net.
uri.arpa. 86400 IN NS c.iana-servers.net.
uri.arpa. 86400 IN NS ns2.lacnic.net.
uri.arpa. 86400 IN NS sec3.apnic.net.
uri.arpa. 600 IN MX 10 pechora.icann.org.
uri.arpa. 3600 IN DNSKEY 256 3 8 (
AwEAAcBi7tSart2J599zbYWspMNGN70IBWb4ziqyQYH9MTB/VCz6WyUK
uXunwiJJbbQ3bcLqTLWEw134B6cTMHrZpjTAb5WAwg4XcWUu8mdcPTiL
Bl6qVRlRD0WiFCTzuYUfkwsh1Rbr7rvrxSQhF5rh71zSpwV5jjjp65Wx
SdJjlH0B )
uri.arpa. 3600 IN DNSKEY 257 3 8 (
AwEAAbNVv6ulgRdO31MtAehz7j3ALRjwZglWesnzvllQl/+hBRZr9QoY
cO2I+DkO4Q1NKxox4DUIxj8SxPO3GwDuOFR9q2/CFi2O0mZjafbdYtWc
3zSdBbi3q0cwCIx7GuG9eqlL+pg7mdk9dgdNZfHwB0LnqTD8ebLPsrO/
Id7kBaiqYOfMlZnh2fp+2h6OOJZHtY0DK1UlssyB5PKsE0tVzo5s6zo9
iXKe5u+8WTMaGDY49vG80JPAKE7ezMiH/NZcUMiE0PRZ8D3foq2dYuS5
ym+vA83Z7v8A+Rwh4UGnjxKB8zmr803V0ASAmHz/gwH5Vb0nH+LObwFt
l3wpbp+Wpm8= )
uri.arpa. 3600 IN DNSKEY 257 3 8 (
AwEAAbwnFTakCvaUKsXji4mgmxZUJi1IygbnGahbkmFEa0L16J+TchKR
wcgzVfsxUGa2MmeA4hgkAooC3uy+tTmoMsgy8uq/JAj24DjiHzd46LfD
FK/qMidVqFpYSHeq2Vv5ojkuIsx4oe4KsafGWYNOczKZgH5loGjN2aJG
mrIm++XCphOskgCsQYl65MIzuXffzJyxlAuts+ecAIiVeqRaqQfr8LRU
7wIsLxinXirprtQrbor+EtvlHp9qXE6ARTZDzf4jvsNpKvLFZtmxzFf3
e/UJz5eHjpwDSiZL7xE8aE1o1nGfPtJx9ZnB3bapltaJ5wY+5XOCKgY0
xmJVvNQlwdE= )
ftp.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 (
20181028080856 20181007175821 47155 uri.arpa.
HClGAqPxzkYkAT7Q/QNtQeB6YrkP6EPOef+9Qo5/2zngwAewXEAQiyF9
jD1USJiroM11QqBS3v3aIdW/LXORs4Ez3hLcKNO1cKHsOuWAqzmE+BPP
Arfh8N95jqh/q6vpaB9UtMkQ53tM2fYU1GszOLN0knxbHgDHAh2axMGH lqM= )
ftp.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 (
20181028103644 20181007205525 47155 uri.arpa.
WoLi+vZzkxaoLr2IGZnwkRvcDf6KxiWQd1WZP/U+AWnV+7MiqsWPZaf0
9toRErerGoFOiOASNxZjBGJrRgjmavOM9U+LZSconP9zrNFd4dIu6kp5
YxlQJ0uHOvx1ZHFCj6lAt1ACUIw04ZhMydTmi27c8MzEOMepvn7iH7r7 k7k= )
ftp.uri.arpa. 3600 IN NSEC http.uri.arpa. NAPTR (
RRSIG NSEC )
ftp.uri.arpa. 604800 IN NAPTR 0 0 "" "" (
"!^ftp://([^:/?#]*).*$!\\1!i" . )
http.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 (
20181029010647 20181007175821 47155 uri.arpa.
U03NntQ73LHWpfLmUK8nMsqkwVsOGW2KdsyuHYAjqQSZvKbtmbv7HBmE
H1+Ii3Z+wtfdMZBy5aC/6sHdx69BfZJs16xumycMlAy6325DKTQbIMN+
ift9GrKBC7cgCd2msF/uzSrYxxg4MJQzBPvlkwXnY3b7eJSlIXisBIn7 3b8= )
http.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 (
20181029011815 20181007205525 47155 uri.arpa.
T7mRrdag+WSmG+n22mtBSQ/0Y3v+rdDnfQV90LN5Fq32N5K2iYFajF7F
Tp56oOznytfcL4fHrqOE0wRc9NWOCCUec9C7Wa1gJQcllEvgoAM+L6f0
RsEjWq6+9jvlLKMXQv0xQuMX17338uoD/xiAFQSnDbiQKxwWMqVAimv5 7Zs= )
http.uri.arpa. 3600 IN NSEC mailto.uri.arpa. NAPTR (
RRSIG NSEC )
http.uri.arpa. 604800 IN NAPTR 0 0 "" "" (
"!^http://([^:/?#]*).*$!\\1!i" . )
mailto.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 (
20181028110727 20181007175821 47155 uri.arpa.
GvxzVL85rEukwGqtuLxek9ipwjBMfTOFIEyJ7afC8HxVMs6mfFa/nEM/
IdFvvFg+lcYoJSQYuSAVYFl3xPbgrxVSLK125QutCFMdC/YjuZEnq5cl
fQciMRD7R3+znZfm8d8u/snLV9w4D+lTBZrJJUBe1Efc8vum5vvV7819 ZoY= )
mailto.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 (
20181028141825 20181007205525 47155 uri.arpa.
MaADUgc3fc5v++M0YmqjGk3jBdfIA5RuP62hUSlPsFZO4k37erjIGCfF
j+g84yc+QgbSde0PQHszl9fE/+SU5ZXiS9YdcbzSZxp2erFpZOTchrpg
916T4vx6i59scodjb0l6bDyZ+mtIPrc1w6b4hUyOUTsDQoAJYxdfEuMg Vy4= )
mailto.uri.arpa. 3600 IN NSEC urn.uri.arpa. NAPTR (
RRSIG NSEC )
mailto.uri.arpa. 604800 IN NAPTR 0 0 "" "" (
"!^mailto:(.*)@(.*)$!\\2!i" . )
urn.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 (
20181028123243 20181007175821 47155 uri.arpa.
Hgsw4Deops1O8uWyELGe6hpR/OEqCnTHvahlwiQkHhO5CSEQrbhmFAWe
UOkmGAdTEYrSz+skLRQuITRMwzyFf4oUkZihGyhZyzHbcxWfuDc/Pd/9
DSl56gdeBwy1evn5wBTms8yWQVkNtphbJH395gRqZuaJs3LD/qTyJ5Dp LvA= )
urn.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 (
20181029071816 20181007205525 47155 uri.arpa.
ALIZD0vBqAQQt40GQ0Efaj8OCyE9xSRJRdyvyn/H/wZVXFRFKrQYrLAS
D/K7q6CMTOxTRCu2J8yes63WJiaJEdnh+dscXzZkmOg4n5PsgZbkvUSW
BiGtxvz5jNncM0xVbkjbtByrvJQAO1cU1mnlDKe1FmVB1uLpVdA9Ib4J hMU= )
urn.uri.arpa. 3600 IN NSEC uri.arpa. NAPTR RRSIG (
NSEC )
urn.uri.arpa. 604800 IN NAPTR 0 0 "" "" (
"/urn:([^:]+)/\\1/i" . )
uri.arpa. 3600 IN SOA sns.dns.icann.org. (
noc.dns.icann.org. 2018100702 10800 3600 1209600 3600 )
;; Query time: 66 msec
;; SERVER: 192.0.32.132#53(192.0.32.132)
;; WHEN: Sun Oct 21 20:39:28 UTC 2018
;; XFR size: 34 records (messages 1, bytes 3941)
uri.arpa. 3600 IN ZONEMD 2018100702 2 0 (
a921ef5658f31bc6ac3e72a000f8d60a1a933153cf1df8be8153925
60c665b14 )
The ROOT-SERVERS.NET zone retreived 2018-10-21.
root-servers.net. 3600000 IN SOA a.root-servers.net. (
nstld.verisign-grs.com. 2018091100 14400 7200 1209600 3600000 )
root-servers.net. 3600000 IN NS a.root-servers.net.
root-servers.net. 3600000 IN NS b.root-servers.net.
root-servers.net. 3600000 IN NS c.root-servers.net.
root-servers.net. 3600000 IN NS d.root-servers.net.
root-servers.net. 3600000 IN NS e.root-servers.net.
root-servers.net. 3600000 IN NS f.root-servers.net.
root-servers.net. 3600000 IN NS g.root-servers.net.
root-servers.net. 3600000 IN NS h.root-servers.net.
root-servers.net. 3600000 IN NS i.root-servers.net.
root-servers.net. 3600000 IN NS j.root-servers.net.
root-servers.net. 3600000 IN NS k.root-servers.net.
root-servers.net. 3600000 IN NS l.root-servers.net.
root-servers.net. 3600000 IN NS m.root-servers.net.
a.root-servers.net. 3600000 IN AAAA 2001:503:ba3e::2:30
a.root-servers.net. 3600000 IN A 198.41.0.4
b.root-servers.net. 3600000 IN MX 20 mail.isi.edu.
b.root-servers.net. 3600000 IN AAAA 2001:500:200::b
b.root-servers.net. 3600000 IN A 199.9.14.201
c.root-servers.net. 3600000 IN AAAA 2001:500:2::c
c.root-servers.net. 3600000 IN A 192.33.4.12
d.root-servers.net. 3600000 IN AAAA 2001:500:2d::d
d.root-servers.net. 3600000 IN A 199.7.91.13
e.root-servers.net. 3600000 IN AAAA 2001:500:a8::e
e.root-servers.net. 3600000 IN A 192.203.230.10
f.root-servers.net. 3600000 IN AAAA 2001:500:2f::f
f.root-servers.net. 3600000 IN A 192.5.5.241
g.root-servers.net. 3600000 IN AAAA 2001:500:12::d0d
g.root-servers.net. 3600000 IN A 192.112.36.4
h.root-servers.net. 3600000 IN AAAA 2001:500:1::53
h.root-servers.net. 3600000 IN A 198.97.190.53
i.root-servers.net. 3600000 IN MX 10 mx.i.root-servers.org.
i.root-servers.net. 3600000 IN AAAA 2001:7fe::53
i.root-servers.net. 3600000 IN A 192.36.148.17
j.root-servers.net. 3600000 IN AAAA 2001:503:c27::2:30
j.root-servers.net. 3600000 IN A 192.58.128.30
k.root-servers.net. 3600000 IN AAAA 2001:7fd::1
k.root-servers.net. 3600000 IN A 193.0.14.129
l.root-servers.net. 3600000 IN AAAA 2001:500:9f::42
l.root-servers.net. 3600000 IN A 199.7.83.42
m.root-servers.net. 3600000 IN AAAA 2001:dc3::35
m.root-servers.net. 3600000 IN A 202.12.27.33
root-servers.net. 3600000 IN SOA a.root-servers.net. (
nstld.verisign-grs.com. 2018091100 14400 7200 1209600 3600000 )
root-servers.net. 3600000 IN ZONEMD 2018091100 4 0 (
327b45e1f70a95eb83e1b9aaaa0642b9e1d0f007db5ce45858cd336a79
78a0239f4517edfd11445f2b9f70900816fdfd )