16:00:10.075±0.003,
16:00:10.085±0.003,
16:00:10.069±0.007,
16:00:10.070±0.010,
What time does the clerk set its clock to?
13. Can DTS run without a UTC source connected to any of the machines in the system? What are the consequences of doing this?
14. Why do distinguished names have to be unique, but not RDNs?
15. Give the X.500 name for the sales department at Kodak in Rochester, NY.
16. What is the function of the CDS clerk? Would it have been possible to have designed DCE without the CDS clerks? What would the consequences have been?
17. CDS is a replicated data base system. What happens if two processes try simultaneously to change the same item in different replicas to different values?
18. If DCE did not support the Internet naming system, which parts of Fig. 10-24 could be dispensed with?
19. During the authentication sequence, a client first acquires a ticket and later a PAC. Since both of them contain the user's ID, why go to the trouble of acquiring a PAC once the necessary ticket has been obtained?
20. What is the difference, if any, between the following messages:
{{message }KA}KC and
{{message }KC}KA.
21. The authentication protocol described in the text allows an intruder to send arbitrarily many messages to the authentication server in an attempt to get a reply containing an initial session key. What weakness does this observation introduce into the system? (Hint: You may assume that all messages contain a timestamp and other information, so it is easy to tell a valid mes sage from random junk.)
22. The text discussed only the case of security within a single cell. Propose a way to do authentication for RPC when the client is in the local cell and server is in a remote cell.
23. Tokens can expire in DFS. Does this require synchronized clocks using DFS?
24. An advantage of DFS over NFS is that DFS preserves single-system file semantics. Name a disadvantage.
25. Why must a clone of a fileset be in the same disk partition?