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.
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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.
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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.
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
|
1035 |
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:
Web UI: Resource Records for Zone page: Name, TTL, Type=A6, Data=prefixlength suffixaddr prefixname, with data in the form:
|
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
|
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
|
1183 |
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:
Web UI: Resource Records for Zone page: Name, TTL, Type=CAA, Data= flag tag value
|
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
|
1035 |
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:
|
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
|
1035 |
HTTPS |
65 |
HTTPS Binding |
name ttl class HTTPS SvcPriority TargetName SvcParams
Web UI: Resource Records for Zone page: Name, TTL, Type=HTTPS, Data=SvcPriority TargetName SvcParams 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 ]
|
1183 |
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
|
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: |
1035 |
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
|
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
|
1035 |
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
|
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
Web UI: Resource Records for Zone page: Name, State, TTL, Type=NAPTR, Data=order pref flags service regexp replace
|
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
|
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
|
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
|
1035 |
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
|
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
|
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
|
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
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
|
2782 |
SVCB |
64 |
Service Binding |
name ttl class SVCB SvcPriority TargetName SvcParams
Web UI: Resource Records for Zone page: Name, TTL, Type=SVCB, Data=SvcPriority TargetName SvcParams 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
|
1035 |
URI |
256 |
Uniform Resource Identifier |
name ttl class URI priority weight target Data contains priority, weight, and target. Where:
Web UI: Resource Records for Zone page: Name, TTL, Type=URI, Data= priority weight target
|
7553 |
WKS |
11 |
Well Known Services |
name ttl class WKS addr protocol servicelist
Web UI: Resource Records for Zone page: Name, TTL, Type=WKS, Data=addr protocol servicelist
|
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
|
1183 |