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Difficulty: EasyDNS Infrastructure and Record Types

Match each DNS resource record type to its primary technical function within an enterprise network infrastructure.

  • SRV RecordDefines the hostname and port number for specific directory or telephony services such as LDAP or SIP.
  • PTR RecordMaps an IP address to a canonical domain name for reverse DNS lookups.
  • MX RecordSpecifies the mail server designated to accept incoming email on behalf of a domain.
  • TXT RecordStores arbitrary text entries used for domain ownership validation, SPF, and DKIM security policies.

Answer

SRV matches service location and port specification; PTR matches reverse DNS resolution from IP to hostname; MX matches mail server designation for email routing; TXT matches domain verification and security policy storage.
Each DNS record type provides distinct functionality: SRV includes port and protocol service locations; PTR maps IP addresses back to domain names for reverse lookups; MX designates incoming mail servers; and TXT holds descriptive text for domain security authentications like SPF.

Step-by-Step Solution

1
Identify the primary function of SRV records.
SRV records include port numbers and target hostnames for network services (e.g., SIP, LDAP, Active Directory).
Different services use specific transport ports, which SRV records explicitly declare.
2
Identify the primary function of PTR records.
PTR records reside in reverse lookup zones (in-addr.arpa or ip6.arpa) to resolve IP addresses back to hostnames.
Reverse resolution enables logging, anti-spam validation, and security verification.
3
Identify the primary function of MX records.
MX records specify incoming mail servers along with priority preference numbers.
SMTP routing depends on MX queries to deliver email to the correct destination host.
4
Identify the primary function of TXT records.
TXT records contain text metadata used by email verification systems (SPF, DKIM, DMARC) and domain authorization mechanisms.
Arbitrary text strings allow domain administrators to publish verification tokens without modifying protocol headers.

Key Concept

DNS Resource Record Functionality and Application
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Topics

DNS Infrastructure and Record Types

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