What is the predecessor to the Domain Name System (DNS)?
A.
Simple Network Management Protocol (SNMP)
B.
Hosts file
C.
NetBIOS
D.
Dynamic Host Configuration Protocol (DHCP)
Explanation:
The HOSTS file was a hardcoded text file containing the IP to Name mappings. When there were
many hosts, this file became large, and grew to the point where it could not be managed. The hard
part was that after the file was changed, getting all the machines to obtain the copy of the new file.
The file grew so large, that it was unmanageable. Think of it this way: There are millions of
domains out there, and probably over a hundred million nodes to be mapped, image a test file with
a hundred million entries in it. Just scanning the file is prohibitive.
Although not mentioned in this problem, let me add this: There is also another file called
LMHOSTS, which is similar to the HOSTS file. However, the LMHOSTS file is for NetBIOS
mappings. HOSTS was replaced by DNS, LMHOSTS was replaced by WINS.
Incorrect Answers:
A: SNMP is an application protocol used to manage networks. It is not related to the DNS service.
C: NetBIOS is a layer 2 protocol that rides on the 802.2 specification. It does not interface with
DNS, where DNS works on IP, a network layer protocol. DNS is an application, its traffic runs on
port 53, all of it UDP traffic, except zone transfers which are TCP.
D: DHCP is a protocol that is used to assign IP addresses. As part of an option, the DHCP
protocol can assign DNS server addresses, but that is as close as DHCP comes to DNS. DHCP
does not provide IP to Name mappings.