Next week we will start the Labs. In order to get ready for Lab#1 you need to get familiar with Wireshark application. You can read
this document that explains how it works. As it is free software, you should have no problem downloading and installing it in your home computer, no matter what operating system you use there is a version available. I want you to capture the traffic to port 53 while you visit one or more web pages and to send me an email detailing the source and destination IP addresses and source and destiantion ports of the captured traffic.
Wireshark doesn't find the network interfaces in my computer if I run it with my user. But running it as root works fine. Is that normal? Do I have to configure something?
ReplyDeleteYes, it is normal behavior. You need admin privileges to be able to capture traffic from the network. As a regular user you can only analyze the content of captures stored to a file previously.
ReplyDeleteI would never think that a normal explorer makes 38 QUERIES to load the main page of Google search.
ReplyDeleteMay I suggest you to try any news site. You'll be surprised about the data transferred plus the number of queries.
ReplyDeleteLooking the queries of a simple blog (even this), it just "pre loads" everything?.
ReplyDeleteWhat about more complex pages, where the content is generated at the moment of the query, and it uses several files. It just pre loads EVERYTHING?, even if they are not used in the "current" page?.
Just look a page where the CSS file has some images linked.
I am afraid so Domingo. A web page is like a blank canvas, all what is shown comes from somewhere, via HTTP protocol. Not all sites are tuned for performance (most are not).
ReplyDelete