In a classful addressing, first four bits in Class A IP address is
2014
In a classful addressing, first four bits in Class A IP address is
- A.
0010
- B.
1100
- C.
1011
- D.
1110
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Correct answer: A
Answer summary: 0010
Key rule: In classfull IPv4 addressing, Class A addresses have the first bit equal to 0. Therefore the four-bit pattern for Class A is any sequence that starts with 0, written as 0xxx.
Implication: The first four bits for Class A can be 0000 through 0111 (any pattern whose first bit is 0).
Example IPv4 range for Class A: 0.0.0.0 to 127.255.255.255 (leading bit 0).
0010: starts with 0, so it is Class A.
1100: starts with 1, so it is not Class A.
1011: starts with 1, so it is not Class A.
1110: starts with 1, so it is not Class A.