The server did not return the contents of the file because the browser simply retrieved the contents from its cache.

The HTTP status code is “304: Not Modified”.

What is the HTTP status code and phrase returned from the server in response to this second HTTP GET? Did the server explicitly return the contents of the file? Explain. The information that follows is the date and time that I last accessed the webpageġ1.

Yes in the second HTTP message an IF-MODIFIED-SINCE line is included.

Do you see an “IF-MODIFIED-SINCE:” line in the HTTP GET? If so, what information follows the “IF-MODIFIED-SINCE:” header? Now inspect the contents of the second HTTP GET request from your browser to the server. Wireshark includes a section titled “Line-Based Text Data” which shows what the server sent back to my browser which is specifically what the website showed when I brought it up on my browser.ġ0.

The server did explicitly return the contents of the file.

Did the server explicitly return the contents of the file? How can you tell? Inspect the contents of the server response. No there is no IF-MODIFIED-SINCE line in the GET message.ĩ.Do you see an “IF-MODIFIED-SINCE” line in the HTTP GET? Inspect the contents of the first HTTP GET request from your browser to the server. Step 5: Stop Wireshark packet capture, and enter “http” in the display-filter-specification window, so that only captured HTTP messages will be displayed later in the packet-listing window.Ĩ. Step 4: Quickly enter the same URL into your browser again (or simply select the refresh button on your browser)

Step 3: Enter the following URL into your browser Your browser should display a very simple five-line HTML file. Step 2: Start up the Wireshark packet sniffer Step 1: Start up your web browser, and make sure your browser’s cache is cleared, as discussed above.

Wireshark http response header