Which IPv6 address is valid?
Click on the arrows to vote for the correct answerA. B. C. D.
An IPv6 address is represented as eight groups of four hexadecimal digits, each group representing 16 bits (two octets). The groups are separated by colons (:).
An example of an IPv6 address is 2001:0db8:85a3:0000:0000:8a2e:0370:7334. The leading 0's in a group can be collapsed using ::, but this can only be done once in an IP address.
The correct answer is D. 2031:0:130F::9C0:876A:130B.
Explanation: IPv6 addresses are 128-bit long and are represented in hexadecimal notation. The notation uses eight groups of four hexadecimal digits, separated by colons (:).
Option A (2001:0db8:0000:130F:0000:0000:08GC:140B) is not valid because hexadecimal notation uses only the digits 0-9 and the letters A-F. The last group contains invalid characters 'G' and 'C'.
Option B (2001:0db8:0:130H::87C:140B) is not valid because 'H' is not a valid hexadecimal digit.
Option C (2031::130F::9C0:876A:130B) is not valid because it contains two consecutive colons (::), which is not allowed in IPv6 address notation.
Option D (2031:0:130F::9C0:876A:130B) is a valid IPv6 address because it has eight groups of four hexadecimal digits separated by colons. The two consecutive colons represent a group of consecutive zeros, and only one occurrence of consecutive colons is allowed in an IPv6 address.