IPv6 addresses are divided into how many blocks, and what is the size of each block?

• A. Four blocks of 8 bits
• B. Six blocks of 16 bits
• C. Eight blocks of 16 bits
• D. Eight blocks of 8 bits

Answer: (C)

IPv6 addresses are 128 bits long and are written as eight blocks, with each block representing 16 bits. Each block is shown in hexadecimal (four digits per block) and separated by colons. For example, a typical IPv6 address looks like xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx. You can drop leading zeros within a block and use a double colon to compress consecutive zero blocks once in an address, but the total still equals eight blocks of 16 bits, totaling 128 bits. The other options don’t fit: four blocks of 8 bits would be 32 bits (IPv4), six blocks of 16 bits would be 96 bits, and eight blocks of 8 bits would be 64 bits.