What is the maximum length for a fully qualified domain name, including the trailing period?
Amazon Route 53 supports the DNS 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 Route 53 using the API. Show
For record types that include a domain name, enter a fully qualified domain name, for example, www.example.com. The trailing dot is optional; Route 53 assumes that the domain name is fully qualified. This means that Route 53 treats www.example.com (without a trailing dot) and www.example.com. (with a trailing dot) as identical. Route 53 provides an extension to DNS functionality known as alias records. Similar to CNAME records, alias records let you route traffic to selected AWS resources, such as CloudFront distributions and Amazon S3 buckets. For more information, including a comparison of alias and CNAME records, see Choosing between alias and non-alias records. Topics
A record typeYou use an A record to route traffic to a resource, such as a web server, using an IPv4 address in dotted decimal notation. Example for the Amazon Route 53 console 192.0.2.1Example for the Route 53 API AAAA record typeYou use an AAAA record to route traffic to a resource, such as a web server, using an IPv6 address in colon-separated hexadecimal format. Example for the Amazon Route 53 console 2001:0db8:85a3:0:0:8a2e:0370:7334Example for the Route 53 API CAA record typeA CAA record specifies which certificate authorities (CAs) are allowed to issue certificates for a domain or subdomain. Creating a CAA record helps to prevent the wrong CAs from issuing certificates for your domains. A CAA record isn't a substitute for the security requirements that are specified by your certificate authority, such as the requirement to validate that you're the owner of a domain. You can use CAA records to specify the following:
When you add a CAA record to your hosted zone, you specify three settings separated by spaces: flags tag "value" Note the following about the format for CAA records:
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Authorize a CA to issue a certificate for a domain or subdomainTo authorize a CA to issue a certificate for a domain or subdomain, create a record that has the same name as the domain or subdomain, and specify the following settings:
For example, suppose you want to authorize ca.example.net to issue a certificate for example.com. You create a CAA record for example.com with the following settings: 0 issue "ca.example.net"For information about how to authorize AWS Certificate Manager to issue a certificate, see Configure a CAA record in the AWS Certificate Manager User Guide. Authorize a CA to issue a wildcard certificate for a domain or subdomainTo authorize a CA to issue a wildcard certificate for a domain or subdomain, create a record that has the same name as the domain or subdomain, and specify the following settings. A wildcard certificate applies to the domain or subdomain and all of its subdomains.
For example, suppose you want to authorize ca.example.net to issue a wildcard certificate for example.com, which applies to example.com and all of its subdomains. You create a CAA record for example.com with the following settings: When you want to authorize a CA to issue a wildcard certificate for a domain or subdomain, create a record that has the same name as the domain or subdomain, and specify the following settings. A wildcard certificate applies to the domain or subdomain and all of its subdomains. Prevent any CA from issuing a certificate for a domain or subdomainTo prevent any CA from issuing a certificate for a domain or subdomain, create a record that has the same name as the domain or subdomain, and specify the following settings:
For example, suppose you don't want any CA to issue a certificate for example.com. You create a CAA record for example.com with the following settings: 0 issue ";" If you don't want any CA to issue a certificate for example.com or its subdomains, you create a CAA record for example.com with the following settings: 0 issuewild ";" If you create a CAA record for example.com and specify both of the following values, a CA that is using the value ca.example.net can issue the certificate for example.com: 0 issue ";" 0 issue "ca.example.net"Request that any CA contacts you if the CA receives an invalid certificate requestIf you want any CA that receives an invalid request for a certificate to contact you, specify the following settings:
For example, if you want any CA that receives an invalid request for a certificate to send email to , you create a CAA record with the following settings: 0 iodef "mailto:"Use another setting that is supported by the CAIf your CA supports a feature that isn't defined in the RFC for CAA records, specify the following settings:
For example, suppose your CA supports sending a text message if the CA receives an invalid certificate request. (We aren't aware of any CAs that support this option.) Settings for the record might be the following: 128 exampletag "15555551212"ExamplesExample for the Route 53 console 0 issue "ca.example.net" 0 iodef "mailto:"Example for the Route 53 API CNAME record typeA CNAME record maps DNS queries for the name of the current record, such as acme.example.com, to another domain (example.com or example.net) or subdomain (acme.example.com or zenith.example.org). 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 records for that subdomain. For example, if you create a CNAME for www.example.com, you cannot create any other records for which the value of the Name field is www.example.com. Amazon Route 53 also supports alias records, which allow you to route queries to selected AWS resources, such as CloudFront distributions and Amazon S3 buckets. Aliases are similar in some ways to the CNAME record type; however, you can create an alias for the zone apex. For more information, see Choosing between alias and non-alias records. Example for the Route 53 console hostname.example.comExample for the Route 53 API DS record typeA delegation signer (DS) record refers a zone key for a delegated subdomain zone. You might create a DS record when you establish a chain of trust when you configure DNSSEC signing. For more information about configuring DNSSEC in Route 53, see Configuring DNSSEC signing in Amazon Route 53. The first three values are decimal numbers representing the key tag, algorithm, and digest type. The fourth value is the digest of the zone key. For more information about the DS record format, see RFC 4034. Example for the Route 53 console 123 4 5 1234567890abcdef1234567890absdefExample for the Route 53 API MX record typeAn MX record specifies the names of your mail servers and, if you have two or more mail servers, the priority order. Each value for an MX record contains two values, priority and domain name. Priority An integer that represents the priority for an 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. The server with the lowest value for the priority takes precedence. 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. Domain nameThe domain name of the email server. Specify the name (such as mail.example.com) of an A or AAAA record. In RFC 2181, Clarifications to the DNS Specification, section 10.3 forbids specifying the name of a CNAME record for the domain name value. (When the RFC mentions "alias," it means a CNAME record, not a Route 53 alias record.) Example for the Amazon Route 53 console 10 mail.example.comExample for the Route 53 API NAPTR record typeA Name Authority Pointer (NAPTR) is a type of record 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 record 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. PreferenceWhen 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. FlagsA 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. ServiceA setting that is specific to DDDS applications. Enclose Service in quotation marks. For more information, see the applicable RFCs:
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:
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 ReplacementThe 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)$!sip:\\!" . 100 51 "u" "E2U+h323" "!^\\+441632960083$!h323:!" . 100 52 "u" "E2U+email:mailto" "!^.*$!mailto:!" .Example for the Route 53 API NS record typeAn NS record identifies the name servers for the hosted zone. Note the following:
For more information about NS records, see NS and SOA records that Amazon Route 53 creates for a public hosted zone. Example for the Amazon Route 53 console ns-1.example.comExample for the Route 53 API PTR record typeA PTR record maps an IP address to the corresponding domain name. Example for the Amazon Route 53 console hostname.example.comExample for the Route 53 API SOA record typeA 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 records that Amazon Route 53 creates for a public hosted zone. Example for the Route 53 console ns-2048.awsdns-64.net hostmaster.awsdns.com 1 1 1 1 60Example for the Route 53 API SPF record typeSPF records were formerly used to verify the identity of the sender of email messages. However, we no longer recommend that you create records 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 the Wikipedia article Sender Policy Framework. Example for the Amazon Route 53 console "v=spf1 ip4:192.168.0.1/16 -all"Example for the Route 53 API SRV record typeAn 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. SRV records are used for accessing services, such as a service for email or communications. For information about SRV record format, refer to the documentation for the service that you want to connect to. Example for the Amazon Route 53 console 10 5 80 hostname.example.comExample for the Route 53 API TXT record typeA TXT record contains one or more strings that are enclosed in double quotation marks ("). When you use the simple routing policy, include all values for a domain (example.com) or subdomain (www.example.com) in the same TXT record. Topics
Entering TXT record valuesA single string can include up to 255 characters, including the following:
If you need to enter a value longer than 255 characters, break the value into strings of 255 characters or fewer, and enclose each string in double quotation marks ("). In the console, list all the strings on the same line: "String 1" "String 2" "String 3"For the API, include all the strings in the same Value element: The maximum length of a value in a TXT record is 4,000 characters. To enter more than one TXT value, enter one value per row. Special characters in a TXT record valueIf your TXT record contains any of the following characters, you must specify the characters by using escape codes in the format \three-digit octal code:
For example, if the value of your TXT record is "exämple.com", you specify "ex\344mple.com". For a mapping between ASCII characters and octal codes, perform an internet search for "ascii octal codes." One useful reference is ASCII Code - The extended ASCII table. To include a quotation mark (") in a string, put a backslash (\) character before the quotation mark: \". Uppercase and lowercase in a TXT record valueCase is preserved, so "Ab" and "aB" are different values. ExamplesExample for the Amazon Route 53 console Put each value on a separate line: "This string includes \"quotation marks\"." "The last character in this string is an accented e specified in octal format: \351" "v=spf1 ip4:192.168.0.1/16 -all"Example for the Route 53 API Put each value in a separate Value element: What is the maximum number of characters in an FQDN quizlet?A fully qualified domain name can contain how many characters? 255; An FQDN is limited to a total length of 255 characters.
What is the character limit on individual domain names and the limit on the fully qualified domain names Fqdns )?The maximum length of the host name and of the fully qualified domain name (FQDN) is 63 bytes per label and 255 characters per FQDN.
What is the last part of an FQDN called?An FQDN is a complete address for a website, computer, server or similar entity that exists on the internet. An FQDN consists of three labels, including the hostname, second-level domain name and top-level domain name (TLD), each separated by a period, ending with a trailing period.
Which of the following would be the correct FQDN for a resource record in a reverse lookup zone if the computer's IP address is 192.168 1.10 1 point?D. Correct: PTR records contain the information needed for the server to perform reverse name lookups. 57. Which of the following would be the correct FQDN for a resource record in a reverse lookup zone if the computer's IP address is 10.75.
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