Which of the following is NOT a correct notation for an IPv6 address? 

Answer options:

A. 2001:0db8:0:0:0:0:1428:57ab
B. ABCD:EF01:2345:6789:ABCD:EF01:2345:6789
C. ::1
D. 2001:DB8::8:800::417A

D

This is not a correct notation for an IPv6 address because the the "::" can only appear once in an address. The use of "::" is a shortcut notation that indicates one or more groups of 16 bits of zeros. ::1 is the loopback address using the special notation Reference: IP Version 6 Addressing Architecture http://tools.ietf.org/html/rfc4291#section-2.1