Which of the following subnets should the technician use?

A network technician is manually configuring the network settings for a new device and is told the network block is 192.168.0.0/20.

Which of the following subnets should the technician use?
A . 255.255.128.0
B. 255.255.192.0
C. 255.255.240.0
D. 255.255.248.0

View Answer

Answer: C

Explanation:

A subnet mask is a binary number that indicates which bits of an IP address belong to the network portion and which bits belong to the host portion. A slash notation (/n) indicates how many bits are used for the network portion. A /20 notation means that 20 bits are used for the network portion and 12 bits are used for the host portion. To convert /20 to a dotted decimal notation, we need to write 20 ones followed by 12 zeros in binary and then divide them into four octets separated by dots. This gives us 11111111.11111111.11110000.00000000 or 255.255.240.0 in decimal.

Reference: https://partners.comptia.org/docs/default-source/resources/comptia-network-n10-008-exam-objectives-(2-0), https://www.techopedia.com/definition/950/subnet-mask