CS107 assignment, due noon Friday, 4/19/02

Answer the following questions. For some of the gopher-related questions, you will need to refer to RFC 1436. For some of the others, you might try using a search engine to find relevant information.

1. What is ISOC? What is the URL of its web site? Where are its offices? What services does it provide?

2. What does the IETF do? If you wanted to attend one of its meetings, what would you have to do?

3. What does the IANA do?

4. Who is/was Jon Postel?

5. IP addresses are allocated to organizations in various sized blocks known as Class A, Class B, and Class C addresses. Many years ago, Carleton was granted control over all the IP addresses that begin with 137.22.

   1. Which class of IP address does Carleton have?
   2. How many different IP addresses does Carleton control?
   3. What is the IP address of blum.mathcs.carleton.edu (the computer in CMC 206)?

6. Unicode characters are stored as 16-bit integers. What 16-bit integer is used to represent the lowercase omega from the Greek alphabet? (Try looking at www.unicode.org.) What is the base-ten value of this integer?

7. Where and when was the gopher protocol developed?

8. The Gopher Manifesto argues in favor of abandoning HTTP for most purposes and returning to widespread use of gopher. List three arguments made by the manifesto's author in favor of gopher.

9. Section 2 of RFC 1436, The Internet Gopher Protocol gives some examples of the interaction between a gopher client and a gopher server.

   1. What happens if a gopher client opens a TCP connection to a gopher server on port 70, and then sends a blank line (that is, a carriage return character followed by a linefeed character, better known as CRLF)?
   2. Login to your Unix account, open a terminal window, and type the command "telnet prism.mathcs.carleton.edu 70". This will open a connection to the gopher server running on prism. What text appears immediately after you hit Enter? Now hit Enter again (this sends a CRLF to the gopher server). What are the first four lines of text the server sends back to you?
   3. Take the first line of text you received when you sent CRLF to prism's gopher server. This line tells you how to obtain the top gopher listing from the main gopher server at the University of Minnesota. Show exactly what you need to do to obtain the U of M's main gopher page using only telnet. Also, show what text the U's gopher server sends back to you.
   4. In the previous exercise, how can you tell when the U's server is done sending you data?
   5. Go back to the original text you retrieved by sending a CRLF to prism's gopher server. This same text tells you how to retrieve the file named "rfc2100.txt". Show exactly how you would retrieve this file using only telnet.
   6. Use Netscape to go to gopher://prism.mathcs.carleton.edu/. Note that some of the entries on this page are displayed using folder icons, and some are displayed with piece-of-paper icons. Netscape constructs the display of this page out of the same text you retrieved by sending CRLF to prism's gopher server. How is Netscape able to decide which lines get a folder icon, and which lines get a piece-of-paper?