Which of the following looks like a correct entry in the /etc/hosts file?

Question

Options

• Alocalhost 127.0.0.1 localhost.localdomain
• Blocalhost.localdomain localhost 127.0.0.1
• Clocalhost localhost.localdomain 127.0.0.1
• D127.0.0.1 localhost.localdomain localhost
• Elocalhost.localdomain 127.0.0.1 localhost

• A
  4% (1)
• C
  4% (1)
• D
  82% (23)
• E
  11% (3)

Explanation

D is correct because /etc/hosts entries always follow the format IP_address hostname [aliases...] - the IP address must come first, followed by the canonical hostname and any aliases. Option D (127.0.0.1 localhost.localdomain localhost) matches this structure exactly.

Why the others are wrong: A, B, C, and E all place a hostname (either localhost or localhost.localdomain) before the IP address, which is the opposite of the required order - the system parser expects to read an IP first and will fail or misinterpret entries that don't start with one.

Memory tip: Think of it as "address before name" - just like writing a mailing address puts the zip code or country after the street, but in /etc/hosts you lead with the numeric address (IP), then follow with human-readable names. If it doesn't start with digits, it's wrong.

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