IPV6 ADDRESS

[jonk34567]

Which option is a valid IPv6 address?
A. 2001:0000:130F::099a::12a
B. 2002:7654:A1AD:61:81AF:CCC1
C. FEC0:ABCD:WXYZ:0067::2A4

D. 2004:1:25A4:886F::1

answer is D . but isnt C also valid ? 

[burleyman]

No....

remember Hex.

Mike

[jonk34567]

i didnt get it. 

[Harold Ritter]

Because the address illustrated in C contains caracters that are not hexadecimal (outside of the 0 thru 9 or A thru F range).

Regards,

[Julio E. Moisa]

Hi

It should be D, now why? The rules are: 

- 0 to 9 and A to F

- You cannot have multiple double colons (::) into the IPV6 address infrastructure. It will group continuous zeros, example:

2001:1000:0000:0000:0000:7777:1234:FE58

it could be: 

2001:1000:0:0:0:7777:1234:FE58

or

2001:1000::7777:1234:FE58

- IPv6 address are built of 128 bits, it is represented by 8 spaces of 16 bits separated by colons, example: 2001:1000:0000:ABCD:1F17:7777:1234:FE58

- You can simplify the initial zeros of each spaces. 

example: 

2001:1000:0000:ABC0:1F17:0007:1234:0058

Simplifying:

2001:1000::ABC0:1F17:7:1234:58

You know that each space if built with 4 values so if you only see 1 you can say it has 3 zeros before 7 and 2 zeros before 58. Also you know double colon (::) is zeros, the key is: remember they are 8 spaces with 16 bits each one. 

Hope it is useful

:-)