Cisco CCNA IPv4 and IPv6 Addressing 4

Question 1

A host has the IP address 10.4.8.77/21. What is the network address of this subnet?

Accepted Answer

10.4.0.0

Answer

A /21 mask covers the first 21 bits; the third octet's top 5 bits identify the subnet — 8 (00001000) ANDed with the mask gives 10.4.0.0.

Question 2

What is the purpose of the IPv6 EUI-64 process?

Accepted Answer

To generate a 64-bit interface ID from a 48-bit MAC address

Answer

EUI-64 inserts FFFE in the middle of a 48-bit MAC address and flips the 7th bit to create a unique 64-bit interface ID.

Question 3

Which statement correctly describes VLSM (Variable Length Subnet Masking)?

Accepted Answer

Subnets can use different prefix lengths to optimize address space

Answer

VLSM allows different subnets within the same address space to use different prefix lengths, enabling efficient IP address utilization.

Question 4

Which IPv4 address block is used for APIPA (Automatic Private IP Addressing) when DHCP is unavailable?

Accepted Answer

169.254.0.0/16

Answer

Windows assigns APIPA addresses from 169.254.0.0/16 when a DHCP server cannot be reached.

Question 5

How many bits make up an IPv6 address?

Accepted Answer

128

Answer

IPv6 addresses are 128 bits long, expressed as eight groups of four hexadecimal digits.

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