What is the primary function of the Simple Mail Transfer Protocol (SMTP)?

Correct answer: To transfer mail from the sender's mail server to the recipient's mail server.

Explanation

SMTP is the core 'push' protocol of the Internet mail system, responsible for moving e-mail messages between mail servers across the Internet.

Other questions

Question 1

From an application developer's perspective, which of the following best describes the network architecture?

Question 2

What is the defining characteristic of the peer-to-peer (P2P) architecture?

Question 3

In the context of a communication session between two processes, how is the 'client' process defined?

Question 4

What two pieces of information are required to identify a specific receiving process on a destination host in the Internet?

Question 5

Which transport layer protocol provides a connection-oriented service and reliable data transfer?

Question 6

What is Transport Layer Security (TLS) and how is it related to TCP?

Question 7

According to the text, what is an 'application-layer protocol' responsible for defining?

Question 8

What is the relationship between the HyperText Transfer Protocol (HTTP) and the World Wide Web application?

Question 9

What are the two components of a URL, as described in the overview of HTTP?

Question 10

HTTP is described as a 'stateless protocol'. What does this mean?

Question 11

To transfer a web page consisting of a base HTML file and 10 JPEG images from the same server using non-persistent HTTP connections, how many TCP connections are generated in total?

Question 12

What is the approximate total response time to request and receive a single HTML file using a non-persistent HTTP connection, expressed in terms of RTT (round-trip time)?

Question 13

What is a primary advantage of using persistent HTTP connections over non-persistent connections?

Question 14

In an HTTP request message, which line specifies the browser type that is making the request?

Question 15

Which HTTP method is typically used when a user fills out a form, and the entity body of the request message contains the user-entered data?

Question 16

What does the HTTP response status code '301 Moved Permanently' signify?

Question 17

What are the four components of cookie technology as described in the text?

Question 18

What is another name for a Web cache, as mentioned in the text?

Question 19

In the example of an institutional network with a 15 Mbps access link, an average object size of 1 Mbits, and a request rate of 15 requests per second, what is the traffic intensity on the access link?

Question 20

What HTTP mechanism allows a cache to verify if its stored objects are up to date without re-downloading the entire object?

Question 21

If a cache sends a conditional GET request and the object has NOT been modified, what HTTP status code does the server return?

Question 22

What is the primary motivation behind the development of HTTP/2?

Question 23

How does HTTP/2 solve the Head of Line (HOL) blocking problem?

Question 24

What are the three major components of the Internet mail system?

Question 26

What is a key restriction of the SMTP protocol that requires multimedia data to be encoded before transfer?

Question 27

In the common e-mail scenario, why does a recipient like Bob need a mail access protocol such as IMAP or HTTP?

Question 28

What is the main task of the Internet's domain name system (DNS)?

Question 29

Besides hostname translation, which of the following is another important service provided by DNS?

Question 30

What is a primary reason the DNS is implemented as a distributed, hierarchical database instead of a single centralized server?

Question 31

What are the three classes of DNS servers in the hierarchy, to a first approximation?

Question 32

What is the function of an authoritative DNS server?

Question 33

In the DNS resolution process shown in Figure 2.19, what type of query is sent from the requesting host (cse.nyu.edu) to its local DNS server (dns.nyu.edu)?

Question 34

What is the purpose of the 'TTL' field in a DNS resource record?

Question 35

What type of DNS resource record (RR) is used to provide the standard hostname-to-IP address mapping?

Question 36

If a company wants its mail server and Web server to have the same aliased hostname, for instance 'enterprise.com', which two DNS record types would be used to distinguish them?

Question 37

In client-server file distribution, if a server with an upload rate of 'us' needs to send a file of size 'F' to 'N' peers, what is the minimum distribution time, assuming it grows linearly with N?

Question 38

What is the primary reason P2P architecture is described as 'self-scaling' for file distribution?

Question 39

In BitTorrent, what is the collection of all peers participating in the distribution of a particular file called?

Question 40

What is the role of a 'tracker' in the BitTorrent protocol?

Question 41

In BitTorrent's trading algorithm, how does a peer (Alice) decide which of her neighbors to send chunks to?

Question 42

What is the typical size of a chunk in the BitTorrent protocol?

Question 43

What is Dynamic Adaptive Streaming over HTTP (DASH)?

Question 44

In the context of DASH, what is the purpose of the manifest file?

Question 45

What is a major problem with providing a streaming video service from a single, massive data center?

Question 46

What are the two main server placement philosophies for Content Distribution Networks (CDNs)?

Question 47

How do most CDNs use DNS to intercept and redirect a user's request to a suitable CDN server?

Question 48

What is the primary difference in how Netflix and YouTube utilize their CDNs, according to the case studies?

Question 49

When programming a UDP client, what information must be attached to a packet before it can be sent through the socket?

Question 50

In TCP socket programming, what is the role of the 'welcoming socket' on the server side?