Daniel Laufer


Homework 1

Part 1

1. 2.1 If the DNS service stopped working, would you stilli be able to surf the Web? Explain why or why not?

A: Theoretically, yes, you'd be able to, if you knew the IP addresses of the sites you're trying to reach. However, without any IP addresses, you wouldn't know how to reach "Google" or others.

2. 2.4 What port numbers are implied by each of the following URIs and why:

  a. https://paypal.com
     --this is HTTPS, so port 443
  b. http://mysite.com:8000/index
     --this is specifying port 8000, even though http is usually port 80.
  c. ssh://root@cs.berkley.edu/tmp/file
     --this is SSH, so port 22

3. Describe why TCP can be considered a "better" protocol for the Transport Layer. Describe why UDP can be considered a "better" protocol for the Transport Layer.

A: TCP can be "better" because it is more reliable. It requires a connection and bi-directional confirmation, and includes error checking, more fields, and larger header files. UDP can be "better" because it is faster and more light-weight. It does not form a connection and is stateless. It does not include error checking nor does it include as many fieds, so it is appropriate where a fast connection is needed with many stateless requests at once, like a game server.

4. HTTP is a stateless protocol. Give two options that we could devise to keep track of users and their states.

A: The obvious ways are through cookies and session variables. Other options include storing data in a database or writing files locally on the user's computer in json/xml.

Part 2

I have created a personal page on my seas account right here! It has at least one image and two links. The website uses bootstrap, jQuery, LESS, and font-awesome. I jacked the template (open-source license) from here: http://startbootstrap.com/template-overviews/freelancer/.

And just to show I know how to upload an image:

Part 3

February 2016
TIME Monday Tuesday Wednesday Thursday Friday Saturday Sunday
8 AM
9 AM
10 AM FNAR 636 FNAR 636 CIT 595r
11 AM
12 PM
1 PM
2 PM
3 PM Ind. Std.
4 PM CIT 595 CIT 595
5 PM
6 PM
7 PM
8 PM

No PHP on school server?


I am currently in school at University of Pennsylvania, studying CS. This is my final semester.

I am passionate about web and app development. I would love to make websites for a living.