Identify the correct order in which the following actions take place in an…
2014
Identify the correct order in which the following actions take place in an interaction between a web browser and a web server.
1. The web browser requests a webpage using HTTP.
2. The web browser establishes a TCP connection with the web server.
3. The web server sends the requested webpage using HTTP.
4. The web browser resolves the domain name using DNS.
- A.
4,2,1,3
- B.
1,2,3,4
- C.
4,1,2,3
- D.
2,4,1,3
Attempted by 622 students.
Show answer & explanation
Correct answer: A
Key idea: the browser must know the server IP and have a transport connection before sending an HTTP request.
Correct order: 4 → 2 → 1 → 3
Resolve the domain name using DNS (4): the browser finds the server's IP address for the requested domain.
Establish a TCP connection with the web server (2): the client and server perform the TCP three-way handshake so data can be exchanged reliably.
The web browser requests a webpage using HTTP (1): the HTTP request is sent over the established TCP connection.
The web server sends the requested webpage using HTTP (3): the server responds with the requested resource over the same connection.
Notes: DNS lookups are often cached so a lookup may be skipped in practice. For HTTPS, a TLS handshake occurs after TCP is established and before the HTTP request is sent.