Which protocol or service uses UDP for a client-to-server communication and TCP for server-to-server communication?SMTPFTPHTTPDNS

The protocol that uses UDP for client-to-server communication and TCP for server-to-server communication is DNS (Domain Name System).

Here's a step-by-step explanation:

1. When a client wants to resolve a domain name to an IP address, it sends a DNS query using UDP to a DNS server. UDP is used because it's faster and more efficient for short messages.

2. If the DNS server doesn't have the requested information, it needs to communicate with other DNS servers to find out. This is done using TCP. TCP is used because it's more reliable and ensures that the data is delivered correctly and in the right order.

3. Once the DNS server has the IP address, it sends it back to the client using UDP.

4. The client can now use this IP address to communicate with the desired server.