A client web browser is directed to the url specifying an html page residing on a remote server such as http://www.example.com. What has to happen BEFORE this server can be contacted? a. Any CSS files associated with the page must be loaded from the server. b. The domain name must be resolved to an IP address using DNS. c. All Javascript scripts must be run. d. The DOM must be built in the browser. e. The index.html page must be loaded into the browser

Write a program in js to. Find the url of the page on which the user is.

Suppose a client sends an HTTP request message with the If-modified-since header. Sup- pose the object in a server has not changed since the last time a client retrieved the object. Then the server will send a response message with the status code:  A. 200 OK B. 404 Not Found C. 304 Not Modified D. none of the above

1. Please access any web site so you that you can capture TCP packets from an HTTP request. 2. Please expand all the fields in the header of your HTTP request packet. Take a screenshot for all the fields in the header fields of the HTTP packet. 3. Please expand all the fields in the header of the TCP packet in your HTTP request packet. Take a screenshot for all the fields in the header of the TCP packets. Please answer the following questions based on your HTTP request, and TCP packets screenshots: 1. What is the method used in your HTTP request? 2. What is the host name you visited? 3. What is the connection status in your HTTP request? 4. What are the source port and destination port, respectively? 5. What are the sequence number and acknowledgement number, respectively? 6. Which flags are set up in the captured packet? Explain what the flags mean.