Your network contains two DHCP servers. The DHCP servers are named DHCP1 and DHCP2. The internal
network contains 1,000 DHCP client computers that are located on a single subnet. A router separates the
internal network from the Internet. The router has a single IP address on the internal interface.
DHCP1 has the following scope information:
Starting IP address: 172.16.0.1
Ending IP address: 172.16.7.254
Subnet mask: 255.255.240.0
You need to provide a fault tolerant DHCP infrastructure that supports the client computers on the internal
network. In the event that a DHCP server fails, allclient computers must be able to obtain a valid IPaddress.
How should you configure DHCP2?
A.
Create a scope for the subnet 172.16.0.0/20. Configure the scope to use a starting IP address of 172.16.8.1
and an ending IP address of 172.16.15.254.
B.
Create a scope for the subnet 172.16.0.0/21. Configure the scope to use a starting IP address of 172.16.0.1
and an ending IP address of 172.16.15.254.
C.
Create a scope for the subnet 172.16.8.0/21. Configure the scope to use a starting IP address of 172.16.8.1
and an ending IP address of 172.16.10.254.
D.
Create a scope for the subnet 172.17.0.0/16. Configure the scope to use a starting IP address of 172.17.0.1
and an ending IP address of 172.17.255.254.
Explanation:
Network 255.255.240.0 = /20 -> 4096-2 addresses
255.255.255.0 = /24 -> 256-2 addresses
255.255.254.0 = /23 -> 512-2 addresses
255.255.252.0 = /22 -> 1024-2 addresses
255.255.248.0 = /21 -> 2048-2 addresses
IP address 172.16.0.1 to 172.16.7.254 -> 8*256 -2 =2048-2 addresses
There are 2048-2 addresses left belind.
Option B (172.16.0.0/21) is ruled out because 172.16.0.1 to 172.16.15.254 are belonged to /20 (not /21)
network
Option C (172.16.8.0/21) is ruled out because 172.16.8.1 to 172.16.10.254 contain 3*256-2 = 766
addresses only (insufficient for 1,000 clients)
Option D (172.17.0.0) is ruled out because of different network 172.17.0.0/16 (vs 172.16.0.0/20)