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Question

Difficulty: EasyDNS Infrastructure and Record Types

A network administrator executes a command-line query to verify how an application alias is configured in the domain zone file. The `dig` output displays the following answer section:

text
;; ANSWER SECTION:
app.example.com. 3600 IN CNAME web-server-01.example.com.

Which DNS record type is being used to map the alias hostname `app.example.com` to the canonical domain name `web-server-01.example.com`?

  1. CNAME recordAnswer
  2. B
    PTR record
  3. C
    AAAA record
  4. D
    MX record

Answer

The CNAME record is used to map an alias domain name to its canonical domain name.
The CNAME (Canonical Name) record is specifically designed to create an alias that points one domain name to another canonical domain name.

Step-by-Step Solution

1
Examine the output snippet from the `dig` command.
The answer section shows `app.example.com. 3600 IN CNAME web-server-01.example.com.`.
The record type field in the resource record explicitly states `CNAME`.
2
Determine the functional role of the identified record type.
CNAME stands for Canonical Name, which creates an alias pointing to another hostname.
When a query is made for `app.example.com`, the DNS resolver follows the CNAME to `web-server-01.example.com` to obtain its IP address.

Key Concept

DNS Resource Record Types (CNAME)
Estimated Time:45s
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Topics

DNS Infrastructure and Record Types

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