Which of the following is the principal weakness of DNS (Domain Name System)?
A.
Lack of authentication of servers, and thereby authenticity of records
B.
Its latency, which enables insertion of records between the time when a record has expired and when it is refreshed
C.
Th e fact that it is a simple, distributed, hierarchical database instead of a singular, relational one, thereby giving rise to the possibility of inconsistencies going undetected for a certain amount of time
D.
The fact that addresses in e-mail can be spoofed without checking their validity in DNS, caused by the fact that DNS addresses are not digitally signed
Explanation:
A: Authentication has been proposed but attempts to introduce stronger authentication into DNS have not found wider acceptance. Authentication services have been delegated upward to higher protocol layers. Applications in need of guaranteeing authenticity cannot rely on DNS to provide such but will have to implement a solution themselves. Page 818.