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Amazon Route 53
Developer Guide (API Version 2013-04-01)

Supported DNS Resource Record Types

Amazon Route 53 supports the DNS resource record types that are listed in this section. Each record type also includes an example of how to format the Value element when you are accessing Amazon Route 53 using the API.

Note

For resource record types that include a domain name, enter a fully qualified domain name, for example, www.example.com. The trailing dot is optional; Amazon Route 53 assumes that the domain name is fully qualified. This means that Amazon Route 53 treats www.example.com (without a trailing dot) and www.example.com. (with a trailing dot) as identical.

A Format

The value for an A record is an IPv4 address in dotted decimal notation.

Example for the Amazon Route 53 console

192.0.2.1

Example for the Amazon Route 53 API

<Value>192.0.2.1</Value>

AAAA Format

The value for a AAAA record is an IPv6 address in colon-separated hexadecimal format.

Example for the Amazon Route 53 console

2001:0db8:85a3:0:0:8a2e:0370:7334

Example for the Amazon Route 53 API

<Value>2001:0db8:85a3:0:0:8a2e:0370:7334</Value>

CNAME Format

A CNAME Value element is the same format as a domain name.

Important

The DNS protocol does not allow you to create a CNAME record for the top node of a DNS namespace, also known as the zone apex. For example, if you register the DNS name example.com, the zone apex is example.com. You cannot create a CNAME record for example.com, but you can create CNAME records for www.example.com, newproduct.example.com, and so on.

In addition, if you create a CNAME record for a subdomain, you cannot create any other resource record sets for that subdomain. For example, if you create a CNAME for www.example.com, you cannot create any other resource record sets for which the value of the Name field is www.example.com.

Amazon Route 53 also supports alias resource record sets, which allow you to route queries to a CloudFront distribution, an Elastic Beanstalk environment, an ELB classic or application load balancer, an Amazon S3 bucket that is configured as a static website, or another Amazon Route 53 resource record set. Aliases are similar in some ways to the CNAME resource record type; however, you can create an alias for the zone apex. For more information, see Choosing Between Alias and Non-Alias Resource Record Sets.

Example for the Amazon Route 53 console

hostname.example.com

Example for the Amazon Route 53 API

<Value>hostname.example.com</Value>

MX Format

Each value for an MX resource record set actually contains two values:

  • An integer that represents the priority for an email server

  • The domain name of the email server

If you specify only one server, the priority can be any integer between 0 and 65535. If you specify multiple servers, the value that you specify for the priority indicates which email server you want email to be routed to first, second, and so on. For example, if you have two email servers and you specify values of 10 and 20 for the priority, email always goes to the server with a priority of 10 unless it's unavailable. If you specify values of 10 and 10, email is routed to the two servers approximately equally.

Example for the Amazon Route 53 console

10 mail.example.com

Example for the Amazon Route 53 API

<Value>10 mail.example.com</Value>

NAPTR Format

A Name Authority Pointer (NAPTR) is a type of resource record set that is used by Dynamic Delegation Discovery System (DDDS) applications to convert one value to another or to replace one value with another. For example, one common use is to convert phone numbers into SIP URIs.

The Value element for an NAPTR resource record set consists of six space-separated values:

Order

When you specify more than one record, the sequence that you want the DDDS application to evaluate records in. Valid values: 0-65535.

Preference

When you specify two or more records that have the same Order, your preference for the sequence that those records are evaluated in. For example, if two records have an Order of 1, the DDDS application first evaluates the record that has the lower Preference. Valid values: 0-65535.

Flags

A setting that is specific to DDDS applications. Values currently defined in RFC 3404 are uppercase- and lowercase letters "A", "P", "S", and "U", and the empty string, "". Enclose Flags in quotation marks.

Service

A setting that is specific to DDDS applications. Enclose Service in quotation marks.

For more information, see the applicable RFCs:

Regexp

A regular expression that the DDDS application uses to convert an input value into an output value. For example, an IP phone system might use a regular expression to convert a phone number that is entered by a user into a SIP URI. Enclose Regexp in quotation marks. Specify either a value for Regexp or a value for Replacement, but not both.

The regular expression can include any of the following printable ASCII characters:

  • a-z

  • 0-9

  • - (hyphen)

  • (space)

  • ! # $ % & ' ( ) * + , - / : ; < = > ? @ [ ] ^ _ ` { | } ~ .

  • " (quotation mark). To include a literal quote in a string, precede it with a \ character: \".

  • \ (backslash). To include a backslash in a string, precede it with a \ character: \\.

Specify all other values, such as internationalized domain names, in octal format.

For the syntax for Regexp, see RFC 3402, section 3.2, Substitution Expression Syntax

Replacement

The fully qualified domain name (FQDN) of the next domain name that you want the DDDS application to submit a DNS query for. The DDDS application replaces the input value with the value that you specify for Replacement, if any. Specify either a value for Regexp or a value for Replacement, but not both. If you specify a value for Regexp, specify a dot (.) for Replacement.

The domain name can include a-z, 0-9, and - (hyphen).

For more information about DDDS applications and about NAPTR records, see the following RFCs:

Example for the Amazon Route 53 console

100 50 "u" "E2U+sip" "!^(\\+441632960083)$!sip:\\1@example.com!" .
100 51 "u" "E2U+h323" "!^\\+441632960083$!h323:operator@example.com!" .
100 52 "u" "E2U+email:mailto" "!^.*$!mailto:info@example.com!" .

Example for the Amazon Route 53 API

<ResourceRecord>
   <Value>100 50 "u" "E2U+sip" "!^(\\+441632960083)$!sip:\\1@example.com!" .</Value>
   <Value>100 51 "u" "E2U+h323" "!^\\+441632960083$!h323:operator@example.com!" .</Value>
   <Value>100 52 "u" "E2U+email:mailto" "!^.*$!mailto:info@example.com!" .</Value>
</ResourceRecord>

NS Format

An NS record identifies the name servers for the hosted zone. The value for an NS record is the domain name of a name server. For more information about NS records, see NS and SOA Resource Record Sets that Amazon Route 53 Creates for a Public Hosted Zone. For information about configuring white label name servers, see Configuring White Label Name Servers.

Example for the Amazon Route 53 console

ns-1.example.com

Example for the Amazon Route 53 API

<Value>ns-1.example.com</Value>

PTR Format

A PTR record Value element is the same format as a domain name.

Example for the Amazon Route 53 console

hostname.example.com

Example for the Amazon Route 53 API

<Value>hostname.example.com</Value>

SOA Format

A start of authority (SOA) record provides information about a domain and the corresponding Amazon Route 53 hosted zone. For information about the fields in an SOA record, see NS and SOA Resource Record Sets that Amazon Route 53 Creates for a Public Hosted Zone.

Example for the Amazon Route 53 console

ns-2048.awsdns-64.net hostmaster.awsdns.com 1 1 1 1 60

Example for the Amazon Route 53 API

<Value>ns-2048.awsdns-64.net hostmaster.awsdns.com 1 1 1 1 60</Value>

SPF Format

SPF records were formerly used to verify the identity of the sender of email messages. However, we no longer recommend that you create resource record sets for which the record type is SPF. RFC 7208, Sender Policy Framework (SPF) for Authorizing Use of Domains in Email, Version 1, has been updated to say, "...[I]ts existence and mechanism defined in [RFC4408] have led to some interoperability issues. Accordingly, its use is no longer appropriate for SPF version 1; implementations are not to use it." In RFC 7208, see section 14.1, The SPF DNS Record Type.

Instead of an SPF record, we recommend that you create a TXT record that contains the applicable value. For more information about valid values, see Sender Policy Framework, SPF Record Syntax.

Example for the Amazon Route 53 console

"v=spf1 ip4:192.168.0.1/16 -all"

Example for the Amazon Route 53 API

<Value>"v=spf1 ip4:192.168.0.1/16 -all"</Value>

SRV Format

An SRV record Value element consists of four space-separated values. The first three values are decimal numbers representing priority, weight, and port. The fourth value is a domain name. For information about SRV record format, refer to the applicable documentation.

Example for the Amazon Route 53 console

10 5 80 hostname.example.com

Example for the Amazon Route 53 API

<Value>10 5 80 hostname.example.com</Value>

TXT Format

A TXT record contains a space-separated list of double-quoted strings. A single string include a maximum of 255 characters. In addition to the characters that are permitted unescaped in domain names, space is allowed in TXT strings. All other octet values must be quoted in octal form. Unlike domain names, case is preserved in character strings, meaning that Ab is not the same as aB. You can include a literal quote in a string by preceding it with a \ character.

Example for the Amazon Route 53 console

"This string includes \"quotation marks\"." "The last character in this string is an accented e specified in octal format: \351"

Example for the Amazon Route 53 API

<Value>"This string includes \"quotation marks\"." "The last character in this string is an accented e specified in octal format: \351"</Value>