Problem 9
Recall that TCP can be enhanced with SSL to provide process-to-process security services, including encryption. Does SSL operate at the transport layer or the application layer? If the application developer wants TCP to be enhanced with SSL, what does the developer have to do?
Problem 10
What is meant by a handshaking protocol?
Problem 11
Why do HTTP, FTP, SMTP, and POP3 run on top of TCP rather than on UDP?
Problem 12
Consider an e-commerce site that wants to keep a purchase record for each of its customers. Describe how this can be done with cookies.
Problem 13
Describe how Web caching can reduce the delay in receiving a requested object. Will Web caching reduce the delay for all objects requested by a user or for only some of the objects? Why?
Problem 13
What is the difference between MAIL FROM: in SMTP and From: in the mail message itself?
Problem 14
How does SMTP mark the end of a message body? How about HTTP? Can HTTP use the same method as SMTP to mark the end of a message body? Explain.
Problem 15
Why is it said that FTP sends control information “out-of-band”?
Problem 15
Read RFC 5321 for SMTP. What does MTA stand for? Consider the following
received spam email (modified from a real spam email). Assuming only
the originator of this spam email is malacious and all other hosts are honest,
identify the malacious host that has generated this spam email.
From - Fri Nov 07 13:41:30 2008
Return-Path:
Problem 16
Read the POP3 RFC, RFC 1939. What is the purpose of the UIDL POP3 command?
