Exercises from Lecture 2

1. Draw a map or flow chart on how you understand the connection or roles between HTTP, FTP, IP, top-level domain names, domains, HTML and DNS.
The link to the flow chart

2. Last week, we created a index.html file that can be accessed through the browser. Change the file permission of this file to 700 and try to access it through the browser. What happens? Why?
If the permission is set to 700, it means that the user (owner) have the full permission (to execute, read and write), meanwhile all other have none permissions. Also not to read the file in a browser. The order of the digits in the number in permission is Owner – Group – World. The number 7 means full permission and 0 means zero permissions.

3. When clicking a link on you website, the browser reports a “404 Not found“. What problem could cause this and how can you solve it? Is this problem occuring on client or server side?
The error is caused client-side, so either the address is wrong, internet is disconnected or something alike. The error can be solved by the user, by correcting the address or reconnect to the internet again. If the error is shown after clicking a link, then it’s probably a bad URL, and the owner of the page must correct it.

4. Your website returns a “403 Forbidden” page when visitors try to access it. What could cause this and how can you solve it? Is this problem occuring on client or server side?
It’s a problem in the client side. It can occur due of missing permission from the client, too many user on the server, the IP address is banned or such. It’s a client-side error, so maybe it can be solved by the user, by provide the right informations or correcting the permissions of the file in the web server.

5. EXTRA: the response time of your website is really slow. What can you do to check what is happening? What tools can you use?
I would use the firebug tool in Firefox (fetched as plugin), find the “Net” tab and watch the traffic in the HTTP request I made to the web server. By watching the time needed to make the request, the file sizes and from where, the files is coming from, I can create a bigger picture of the HTTP traffic and figure what is happing. Otherwise I could use the Developer Tool in Google Chrome to see the same thing as Firebug.