Which of the following can use both TCP and UDP?
- Telnet
- FTP
- SSL
- DNS
EXPLANATION
The correct answer is TCP- Transfers; UDP- Queries. The DNS uses TCP
Port 53 for zone transfers, for maintaining coherence between the DNS
database and the server. The UDP protocol is used when a client sends a
query to the DNS server.
The TCP protocol should not be used for queries
as it gives a lot of information, which is useful to attackers. To
remember this just note the capitalized letters are unique to each
other: Tcp = Transfer and Udp = qUeries.
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