Resource Records

This chapter lists all the resource record types supported in Cisco Prime Network Registrar.

Resource Records

Resource records comprise the data within a DNS zone. There is no fixed limit to the number of resource records a zone can own. In general, there can be zero, one, or more resource records of a given type. However, there are constraints on the number of certain types of records a zone can have.

All resource records have these required entries:

  • Name—Name (host) that owns the record, such as example.com.

  • Class (not required for all formats)——DNS supports only the IN (Internet) class of record.

  • TTL—Amount of time to store the record in cache, in seconds. If you do not include a TTL, Cisco Prime Network Registrar uses the zone default TTL, defined in the SOA resource record.

  • Type—Type of the record, such as A, NS, SOA, MX, and so on. There are many types that various RFCs define, although ten or fewer are in common use.

  • Record data—Data types whose format and meaning varies with record type.

The following table lists all the resource record types Cisco Prime Network Registrar supports. It provides the field syntax and the field descriptions, as well as how the fields are represented in the Cisco Prime Network Registrar GUI.

Table 1. Resource Records
Record No. Name Syntax and Description RFC

A

1

Host Address— Name-to-address mapping for the zone

name ttl class A address

Web UI: Add or Edit Host for Zone page: Hostname, IP Address or Resource Records for Zone page: Name, TTL, Type, Data

CLI Command:
nrcmd> zone example.com addRR host123 3600 IN A 192.168.40.123

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A6

38

IPv6 Address— (Obsolete; use AAAA records instead)

name ttl class A6 address

In the data, the suffix address is an IPv6 address encoded in network order (high-order octet first). There must be exactly enough octets in this field to contain a number of bits equal to 128 minus prefix length, with 0 to 7 leading pad bits to make this field an integral number of octets. Pad bits, if present, must be set to zero when loading a zone file and ignored on reception. For example: 

2001:0:734c:c0::

Web UI: Resource Records for Zone page: Name, TTL, Type=A6, Data=prefixlength suffixaddr prefixname, with data in the form:

CLI Command:
0 2345:00c1:ca11:0001:1234:5678:9abc:def0
 
nrcmd> zone example.com addRR host456 A6 0 1345:c1:ca11:1:1234:5678:9abc:def0

6563

AAAA

28

IPv6 Address

name ttl class AAAA address

Data is the IPv6 address format of eight sets of four hexadecimal digits, separated by colons. The first set of four digits is the high-order 16 bits of the address. You can omit leading zeros in sets and omit a value in a set if the value of the set is zero.

Web UI: Resource Records for Zone page: Name, TTL, Type=AAAA, Data=address

CLI Command:
nrcmd> zone example.com addRR host456 AAAA 1345:c1:ca11:1:1234:5678:9abc:def0

3596

AFSDB

18

Andrew File System (AFS) Data Base

name ttl class AFSDB subtype hostname

Subtype is either 1—AFS cell database server, or 2—DCE authentication name server. Hostname is the domain name of host that has a server for the cell named by the owner.

Web UI: Resource Records for Zone page: Name, TTL, Type=AFSDB, Data=subtype hostname

CLI Command:
nrcmd> zone example.com addRR host4 AFSDB 1 AFSDBhost.example.com.

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AXFR

252

Authoritative Zone Transfer

Transfer entire zone file from the primary name server to secondary name servers. AXFR records are not used in ordinary zone files. Rather, they are used on a secondary DNS server to replicate the zone file from a primary DNS server.

Web UI: Resource Records for Zone page: Name, TTL, Type=AXFR, Data=Auth Zone Transfer

1995

CAA

257

Certification Authority Authorization

name ttl class CAA flag tag value

Data contains flag, tag, and value. Where:

  • flag—A byte size. Currently, bit 0 and bit 7 are used, and other bits are reserved for future use (supported values: 0, 1, and 128).
  • tag—A non-zero sequence of US-ASCII letters and numbers. The tag length must be at least 1 and no more than 15.
  • value—A character-string.

Web UI: Resource Records for Zone page: Name, TTL, Type=CAA, Data= flag tag value

CLI Command:
nrcmd> zone example.com addRR test1 CAA 0 issue comodoca.com

6844

CNAME

5

Canonical Name— Aliases or nicknames

alias ttl class CNAME canonicalname

You cannot have any other resource records associated with a CNAME. Aliases are useful when you want the outside world to know a single, easily remembered name. You can also use aliases when a host changes its name. In that case, ensure that you have a CNAME pointer so that when people use the original name, it can be resolved to the newer one.

Web UI: Resource Records for Zone page: Name=alias, TTL, Type=CNAME, Type, Data=canonicalname

CLI Command:
nrcmd> zone example.com addRR host456 CNAME host1234

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DHCID

49

Dynamic Host Configuration Identifier— (RFC 4701)

name ttl class DHCID data

The DNS server uses this RR to allow DHCP clients and servers to update DNS automatically. This RR is not user-configurable. The data is the result of a one-way hash computation of the client message and the domain name. Sample RR output for an IPv6 address: 

chi6.example.com IN DHCID (AAIBY2/AuCccgoJbaxcQc9TUapptP691OjxfNuVAA2kjEA= )

4701

HINFO

13

Host Info— Hardware and software information for the host

name ttl class HINFO cpu os

Data is the hardware (CPU) and operating system.

Web UI: Resource Records for Zone page: Name, TTL, Type=HINFO, Data=cpu os

CLI Command:
nrcmd> zone example.com addRR host5 HINFO CPU1 OS2

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HTTPS

65

HTTPS Binding

name ttl class HTTPS SvcPriority TargetName SvcParams

  • SvcPriority—The priority of this record (relative to others, with lower values preferred). A value of 0 indicates AliasMode.

  • TargetName—The domain name of either the alias target (for AliasMode) or the alternative endpoint (for ServiceMode).

  • SvcParams (optional)—A list of key=value pairs describing the alternative endpoint at TargetName.

Web UI: Resource Records for Zone page: Name, TTL, Type=HTTPS, Data=SvcPriority TargetName SvcParams

CLI Command:
nrcmd> zone example.com addRR cdn1 HTTPS 1 h3pool alpn=h
Note: "ech" service parameter is not supported.

ISDN

20

Integrated Services Digital Network (ISDN) Address

name ttl class ISDN ISDNnumber [subaddr ]

Data is the ISDN number of the owner and Direct Dial In, if any, and an optional ISDN subaddress string

Web UI: Resource Records for Zone page: Name, TTL, Type=ISDN, Data=ISDNnumber [subaddr ]

CLI Command:
nrcmd> zone example.com addRR host6 ISDN ISDN88888

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IXFR

251

Incremental Zone Transfer

Incremental transfer (IXFR) is an efficient means to transfer changes in zones from IXFR servers to IXFR clients. As proposed it is more efficient mechanism as it transfers only the changed portion(s) of a zone. The goal of these mechanism is to enable a set of DNS name servers to remain coherently authoritative for a given zone.

Web UI: Resource Records for Zone page: Name, TTL, Type=IXFR

1995

MB

7

Mailbox Domain Name

name ttl class MB mbox

Data is the domain name of the host with the specified mailbox.

Web UI: Resource Records for Zone page: Name, TTL, Type=MB, Data=mbox

CLI Command:
nrcmd> zone example.com addRR host7 MB mailbox.example.com.

1035

MD

3

Mail Destination- (Obsolete; use MX instead)

A mail destination (OBSOLETE - use MX)

1035

MF

4

Mail Forwarder- (Obsolete; use MX instead)

A mail forwarder (OBSOLETE - use MX)

1035

MG

8

Mail Group Member

name ttl class MG mgroup

Data is the domain name of the mailbox group (mailing list).

Web UI: Resource Records for Zone page: Name, TTL, Type=MG, Data=mgroup

CLI Command:

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MINFO

14

Mailbox Info

name ttl class MINFO respmbox errormbox

Data is the mailbox responsible for the mailing list, and the mailbox to receive error messages.

Web UI: Resource Records for Zone page: Name, TTL, Type=MINFO, Data=respmbox errormbox

CLI Command:
nrcmd> zone example.com addRR host7 MINFO resp.example.com. error.example.com.

1035

MR

9

Mail Rename

name ttl class MR newmbox

Data is the mailbox name to rename the owner mailbox.

Web UI: Resource Records for Zone page: Name, TTL, Type=MR, Data=newmbox

CLI Command:
nrcmd> zone example.com addRR host7 MR renamemb.example.com.

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MX

15

Mail Exchanger— Where to deliver the mail for a domain name

name ttl class MX pref mxname

Data is the preference value (16-bit integer for the preference for the record, with lower values having preference), and the domain name of the mail exchanger for the owner.

Web UI: Resource Records for Zone page: Name, TTL, Type=MX, Data=pref mxname

CLI Command:
nrcmd> zone example.com addRR host8 MX 10 exchanger.example.com.

1035

NAPTR

35

Naming Authority Pointer— Produces a new domain label or Uniform Resource Identifier (URI). You can then use DNS to look up services for many resource names that are not in domain name syntax.

name ttl class NAPTR order pref flags serv regexp replace

  • order —16-bit integer for the order in which to process the NAPTR records to ensure the correct ordering of rules, with low numbers processed before high numbers.

  • pref —16-bit unsigned integer for the order in which to process NAPTR records with equal order values, with low numbers processed before high numbers.

  • flags —Character-string containing flags to control aspects of rewriting and interpreting fields, single characters from the set [A-Z0-9] (not case-sensitive); the S, A and U flags denote a terminal lookup, the P flag says that the remainder of the application-side algorithm should be carried out protocol-specific.
  • serv —Valid protocols or services.
  • regexp —String containing a substitution expression applied to the original string held by the client to construct the next domain name to look up. (For common regex usage, see the "Common Regex Values" table in Cisco Prime Network Registrar 11.2 Administration Guide).
  • replace —Next FQDN to query for NAPTR, SRV, or address records, depending on the value of the flags field.

Web UI: Resource Records for Zone page: Name, State, TTL, Type=NAPTR, Data=order pref flags service regexp replace

CLI Command:
nrcmd> zone 8.6.4.e164.arpa addRR 4.3.2.1.6.7.9 naptr 100 10 u sip+E2U /^.*$/sip:info@tele2.se/ .

2915

NS

2

Name Server— Authoritative server for the zone

name ttl class NS nameserver

Machines that provide name service must not reside in the owner domain. For each domain, you must have at least one NS record. NS records for a domain must exist in both the zone that delegates the domain and in the domain itself. NS record names must have an equivalent A record (they cannot point to an alias).

Web UI: Add or Edit Zone page Nameservers: NS TTL, Add Nameserver

CLI Command:
nrcmd> zone example.com addRR @ NS DNSserv2.example.com.

1035

NSAP

22

Network Service Access Point (NSAP) Address

name ttl class NASP NSAPaddr

Data is the NSAPaddr —Octet values assigned by the assigning authority, a character string of the type used in TXT and HINFO records (see RFC 1706).

Web UI: Resource Records for Zone page: Name, TTL, Type=NSAP, Data=NSAPaddr

CLI Command:
nrcmd> zone example.com addRR host10 NSAP 39840f80005a0000000001e13708002010726e00

1706

NSEC

47

Next Secure record

Part of DNSSEC—used to prove a name does not exist. Uses the same format as the (obsolete) NXT record.

Web UI: Resource Records for Zone page: Name, TTL, Type=NSEC, Data=Next Secure record

OPT

41

DNS EDNS(0) Options

This is a "pseudo DNS record type" needed to support EDNS. An OPT pseudo-RR (sometimes called a meta-RR) MAY be added to the additional data section of a request. If an OPT record is present in a received request, compliant responders MUST include an OPT record in their respective responses.

Web UI: Resource Records for Zone page: Name, TTL, Type=OPT

PTR

12

Pointer— Reverse mapping

name ttl class PTR dname

Data is the domain name of host having the reverse record indicated by the owner. PTR records are used for reverse mapping, specifically in the in-addr.arpa zones for translation of addresses to names. PTRs use official names, not aliases. The name in a PTR record is the local IP address portion of the reverse name.

Web UI: Resource Records for Zone page: Name, State, TTL, Type=PTR, Data=dname

CLI Command:
nrcmd> zone example.com addRR 45.40.168.192.in-addr.arpa. PTR host1234

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RP

17

Responsible Person

name ttl class RP mbox txthost

Data is the domain name of the mailbox for the responsible person, and the domain name of host where TXT records exist.

Web UI: Resource Records for Zone page: Name, TTL, Type=RP, Data=mbox txthost

CLI Command:
nrcmd> zone example.com addRR host7 RP resp.example.com. text.example.com.

1183

RT

21

Route Through

name ttl class RT pref intermediatehost

Data is the pref —16-bit integer for preference to give to this record among others of the same owner, and intermediatehost —domain name of the host serving as intermediate to reach the owner.

Web UI: Resource Records for Zone page: Name, TTL, Type=RT, Data=pref intermediatehost

CLI Command:
nrcmd> zone example.com addRR host7 RT 10 routthru.example.com.

1183

SOA

6

Start of Authority— Every zone must have a single SOA record

name ttl class SOA primeserver hostadmin (serial refresh retry expire minimum)

Web UI: Add or Edit Zone page SOA Attributes: Serial Number, SOA TTL, Nameserver, Contact E-Mail, Secondary Refresh, Secondary Retry, Secondary Expire, Minimum TTL

CLI Command:
nrcmd> zone example.com addRR @ 172800 IN SOA ns hostadmin 1 10800 3600 604800 86400

1035

SPF

99

Sender Policy Framework

Sender Policy Framework (SPF) record is a type of Domain Name Service (DNS) TXT record that identifies which mail servers are permitted to send email on behalf of your domain. The purpose of an SPF record is to detect and prevent spammers from sending messages with forged From addresses on your domain.

SPF records are defined as a single string of text.

7208

SRV

33

Service Location

name ttl class SRV priority weight port target

  • priority —16-bit priority to give the record among the owner SRV records.
  • weight —16-bit load to give the record at the same priority level.
  • port —16-bit port on which to run the service.
  • target —Domain name of host running on the specified port.

Administrators can use several servers for a single domain, move services between hosts with little difficulty, and designate some hosts as primary servers for a service and others as backups. Clients ask for a specific service or protocol for a domain and receive the names of any available servers.

Web UI: Resource Records for Zone page: Name, TTL, Type=SRV, Data=priority weight port target

CLI Command:
nrcmd> zone example.com addRR host2 SRV 10 1 60 host7.example.com.

2782

SVCB

64

Service Binding

name ttl class SVCB SvcPriority TargetName SvcParams

  • SvcPriority—The priority of this record (relative to others, with lower values preferred). A value of 0 indicates AliasMode.

  • TargetName—The domain name of either the alias target (for AliasMode) or the alternative endpoint (for ServiceMode).

  • SvcParams (optional)—A list of key=value pairs describing the alternative endpoint at TargetName.

Web UI: Resource Records for Zone page: Name, TTL, Type=SVCB, Data=SvcPriority TargetName SvcParams

CLI Command:
nrcmd> zone example.com svc4 SVCB 3 svc4.example.net alpn="bar" port="8004"
Note: "ech" service parameter is not supported.

TSIG

250

Transaction Signature

Key name, which must be unique on client and server. Can be used to authenticate dynamic updates as coming from an approved client, or to authenticate responses as coming from an approved recursive name server similar to DNSSEC.

2854

TXT

16

Text

name ttl class TXT textstring

Data is one or more text character strings that can contain any type of information.

Web UI: Resource Records for Zone page: Name, TTL, Type=TXT, Data=textstring

CLI Command:
nrcmd> zone example.com addRR host2 TXT "this message"

1035

URI

256

Uniform Resource Identifier

name ttl class URI priority weight target

Data contains priority, weight, and target. Where:

  • priority—The priority of the target URI in this RR. Its range is 0-65535. Lower the value means, it is more preferred.
  • weight—A relative weight for records with the same priority. Its range is 0-65535. Higher value means, it is more preferred.
  • target—The URI of the target, enclosed in double-quotes. The length of this field must be greater than zero.

Web UI: Resource Records for Zone page: Name, TTL, Type=URI, Data= priority weight target

CLI Command:
nrcmd> zone example.com addRR _ftp._tcp URI 10 1 “ftp://ftp1.example.com/public”

7553

WKS

11

Well Known Services

name ttl class WKS addr protocol servicelist

  • addr —32-bit IP address.
  • protocol —8-bit IP protocol number, which can be TCP or UDP.
  • servicelist —Variable-length bit map in 8-bit multiples of services, which can be TIME, TELNET, FTP, or SMTP.

Web UI: Resource Records for Zone page: Name, TTL, Type=WKS, Data=addr protocol servicelist

CLI Command:
nrcmd> zone example.com addRR host8 WKS 192.168.40.56 TCP TELNET

1035

X25

19

X.25 Address

name ttl class X25 PSDNaddr

Data is the character string of the Public Switch Data Network (PSDN) address in the X.121 numbering plan associated with the owner.

Web UI: Resource Records for Zone page: Name, TTL, Type=X25, Data=PSDNaddr

CLI Command:
nrcmd> zone example.com addRR host9 IN X25 311061700956

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