Cryptography - plaintext to ciphertext to preserve confidentiality.
What is the secret?
- Examining the HTTP protocol with ethereal. Downloading a web
page without using a web browser client like Konqueror or Netscape
or Internet Explorer. Using telnet to connect to port #80 and
speak the www or http protocol. How is this like Monday's class
and handout where we connected to port #25 and gave commands in the
format and language of the SMTP protocol?
- Using the ethereal program. Day #3. Seeing the three-way handshake of TCP.
Study pages 108-109 of Chapter 6.
- Client sends a SYN packet indicating is wants to talk, i.e. to establish
a connection (TCP is connection oriented protocol). Let's connect. Lets hookup.
- Server says OK with an ACK packet flag, but also has the SYN flag set. The 2nd
handshake to occur is thus a SYN/ACK flagged packet from the server back to the
- The client then sends an ACK flagged packet back to the server, and the three-way
handshake is complete. A connection is established.
- The Caeser enciphering of
UNI Panthers using every possible key. There are only 25 keys.
Assignment #1 is now posted (Wednesday) and
will be due on Monday.
- Pretty Good Privacy
- IP numbers and class A, class B and class C networks.
We did NOT cover anything about subnet masks, but the class A, B and C material will be
useful to help you understand today's class and the 0xxxxxxx, 10xxxxxx, and 110xxxxx A, B and
C network divisions. UNI is a class B network, and 134 in binary is 10000110.
The address of the UNI web server at www.uni.edu is 188.8.131.52 and the address of the
UNI College of Natural Sciences web server www.cns.uni.edu is 184.108.40.206.
Please IGNORE the subnet mask material, we will cover that later on.
- We used the following commands to find out the IP number of www.uni.edu: