Describe the structure of the IPv4 packet and the role of the major fields in the packet header! Describe the structure of the IPv6 packet and the role of the major fields in the packet header! Describe the operation of the hosts packet forwarding process and the role of the default gateway! What happens if the default gateway is not configured? Look at the routing table of your computer! Analyze the different entry! Describe the operation of the router packet forwarding process. Describe the structure of the router routing table and the structure of the individual entries! What are the important parameters and settings of a network router or a switch, which we need to be set correctly? Describe the task of the address resolution and the operation of the ARP protocol!

1. Describe the structure of the IPv4 packet and the role of the major fields in the packet header!
2. Describe the structure of the IPv6 packet and the role of the major fields in the packet header!
3. Describe the operation of the hosts packet forwarding process and the role of the default gateway! What happens if the default gateway is not configured?
4. Look at the routing table of your computer! Analyze the different entry!
5. Describe the operation of the router packet forwarding process.
6. Describe the structure of the router routing table and the structure of the individual entries!
7. What are the important parameters and settings of a network router or a switch, which we need to be set correctly?
8. Describe the task of the address resolution and the operation of the ARP protocol!
9. Many business computers have three distinct and worldwide unique identifiers. What are they?
10. DNS uses UDP instead of TCP. If a DNS packet is lost, there is no automatic recovery. Does this cause a problem, and if so, how is it solved?
11. Can a machine with a single DNS name have multiple IP addresses? How could this occur?
12. The number of companies with a Web site has grown explosively in recent years. As a result, thousands of companies are registered in the com domain, causing a heavy load on the top-level server for this domain. Suggest a way to alleviate this problem without changing the naming scheme (i.e., without introducing new top-level domain names). It is permitted that your solution requires changes to the client code.
13. Electronic mail systems need directories so people’s email addresses can be looked up. To build such directories, names should be broken up into standard components (e.g., first name, last name) to make searching possible. Discuss some problems that must be solved for a worldwide standard to be acceptable.
14. A large law firm, which has many employees, provides a single email address for each employee. Each employee’s email address is <login>@lawfirm.com. However, the firm did not explicitly define the format of the login. Thus, some employees use their first names as their login names, some use their last names, some use their initials, etc. The firm now wishes to make a fixed format, for example:

firstname.lastname@lawfirm.com,

that can be used for the email addresses of all its employees. How can this be done without rocking the boat too much?

15. Suppose that John just set up an auto-forwarding mechanism on his work email address, which receives all of his business-related emails, to forward them to his personal email address, which he shares with his wife. John’s wife was unaware of this, and activated a vacation agent on their personal account. Because John forwarded his email, he did not set up a vacation daemon on his work machine. What happens when an email is received at John’s work email address?

16. In any standard, such as RFC 5322, a precise grammar of what is allowed is needed so that different implementations can interwork. Even simple items have to be defined carefully. The SMTP headers allow white space between the tokens. Give two plausible alternative definitions of white space between tokens

17. Is the vacation agent part of the user agent or the message transfer agent? Of course, it is set up using the user agent, but does the user agent actually send the replies? Explain your answer.

18. Does Webmail use POP3, IMAP, or neither? If one of these, why was that one chosen? If neither, which one is it closer to in spirit?

19. Is it possible that when a user clicks on a link with Firefox, a particular helper is started, but clicking on the same link in Internet Explorer causes a completely different helper to be started, even though the MIME type returned in both cases is identical? Explain your answer.

20. Sloth Bank wants to make online banking easy for its lazy customers, so after a customer signs up and is authenticated by a password, the bank returns a cookie containing a customer ID number. In this way, the customer does not have to identify himself or type a password on future visits to the online bank. What do you think of this idea? Will it work? Is it a good idea?

21. Does it make sense for a single ISP to function as a CDN? If so, how would that work? If not, what is wrong with the idea?

22. Describe the structure of the domain name system and the process of name resolution!

23. Describe the process of sending and receiving emails! What are the protocols required for each process to work?