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HTTP GET/response

Initial GET response from server
figure1: Initial GET response from server

is your browser running HTTP version 1.0 or 1.1? What version of HTTP is the server running?

They both uses HTTP/1.1 as the server’s response show HTTP/1.1 200 OK

What languages (if any) does the browser indicate that it can accept to the server?

It accepts locale en-GB

What is the IP address of your computer? of the www.cas.mcmaster.ca server?

DeviceIP Address
Computer192.168.2.23
Server130.113.68.10

What is the status code returned from the server to your browser?

200

When was the HTML file that you are retrieving last modified at the server?

From the header, Last-Modified show Sun, 10 Jan 2021 18:05:48 GMT

Frame
figure2: Frame

How many bytes of content are being returned to your browser?

For text/html it returns 446 bytes, whereas for text/plain it was 1253 bytes

By inspecting the raw data in the packet content window, do you see any headers within the data that are not displayed in the packet-listing window? If so, name one.

The packet-listing windows doesn’t show the full headers comparing to the detailed raw data. One example is Accept-Encoding: gzip, deflate\r\n, which indicates the type of content encoding/compression that the browser can handle.

HTTP CONDITIONAL GET/response interaction

not modified requests
figure3: not modified requests

How many HTTP GET requests were sent?

There are two GET requests sent, according to two refreshes.

How many HTTP response messages were received?

There are two responses received.

If multiple response messages were received, what are the difference between them?

Side-by-side comparison
figure4: Side-by-side comparison

Seems like the difference relies on Keep-Alive header, as well as the date it was being accessed (given that they are executed consecutively.)

Long documents

Long documents
figure5: Long documents

How many HTTP GET request messages did you browser send? Which packet number in the trace contains the GET message for the Bill of Rights?

1 GET req, with packet number 2459.

Which packet number in the trace contains the status code and phrase associated with the response to the HTTP GET request?

Packet number 2466, with the phrase “HTTP/1.1 200 OK”

What is the status code and phrase in the response?

Status code 200 and phrase “HTTP/1.1 OK”

How many data-containing TCP segments were needed to carry the single HTTP response and the text of the Bill of Rights?

7 TCP segments, from 2460-2467 (with 2461, 2463, 2464 as TCP PDU)

HTML documents with Embedded Objects

GET with Embedded objects
figure6: GET with Embedded objects

How many HTTP GET request messages did your browser send? To which Internet addresses were these GET requests sent?

3 GET request, to 130.113.68.10, 23.10.168.63, and 128.119.245.12

Can you tell whether your browser downloaded the two images serially, or whether they were downloaded from the two web sites in parallel? Explain.

The packets 182 and 186 are sent almost simultaneously, meaning parallel downloading (as their are essentially no waiting period between requests) (also known as pipelining in web browser.)

HTML Authentication

What is the server’s response (status code and phrase) in response to the initial HTTP GET message from your browser?

Returns 401 with “HTTP/1.1 401 Authorization Required”, indicating there are authentication involved.

When your browser’s sends the HTTP GET message for the second time, what new field is included in the HTTP GET message?

While the second GET request gives the same field, until the last GET request (8863) it then included the headers Authorization as password