3rd long LEC 8 PT.1

Question 1

T/F

The client/server programs can be divided into
two categories.

Answer 1

True

Question 2

two categories of client/serve programs

Answer 2

directly used by the user, such as email

support other programs

Question 3

____ is a supporting program that is used by other programs such as email

Answer 3

Domain Name System (DNS)

Question 4

To be unambiguous, the names assigned to machines must be carefully selected from a _____ with complete control over the binding between the names and IP addresses

Answer 4

name space

Question 5

2 ways to organize name space

Answer 5

Flat

Hierarchical

Question 6

a name in this space is a sequence of characters without structure

Answer 6

Flat

Question 7

each name is made of several parts

Answer 7

hierarchical

Question 8

___ cannot be used in a large system such as the Internet because it must be centrally controlled to avoid ambiguity and duplication.

Answer 8

flat

Question 9

the names are defined in an inverted-tree structure with the root at the top. The tree can have only 128 levels:

Answer 9

domain name space

Question 10

T/F

The information contained in the domain name space
must be stored

Answer 10

True

Question 11

T/F

it is very inefficient and also unreliable to have just one computer store such a huge amount of information.

Answer 11

True

Question 12

____ what a server is responsible for or has authority over; contiguous
part of the entire tree

Answer 12

zone

Question 13

T/F

If the domain is not divided into smaller domains, domain and zone refer
to the same thing.

Answer 13

true

Question 14

______ is a server whose zone consists of the whole tree.

Answer 14

root server

Question 15

T/F

A root server usually does not store any information about domains but delegates its authority to other servers, keeping references to those servers.

Answer 15

True

Question 16

______ is a server that stores a file

about the zone for which it is an authority.

Answer 16

primary server

Question 17

____ is responsible for creating,maintaining,

and updating the zone file.

Answer 17

primary server

Question 18

______ is a server that transfers

the complete information about a zone from another server (primary or secondary) and stores the file on its local disk.

Answer 18

secondary server

Question 19

T/F

A primary server loads all information from the disk file; the secondary server
loads all information from the primary server.

Answer 19

True

Question 20

______ is when the secondary downloads information from the primary

Answer 20

zone transfer

Question 21

___ is a protocol that can be used in different platforms

Answer 21

DNS

Question 22

3 sections of the domain name space (tree) in the internet

Answer 22

generic domains, country domains, inverse domains

Question 23

Mapping a name to an address or an address to a

name is called ______

Answer 23

name-address resolution

Question 24

_____expects the server to supply the final answer

Answer 24

resolver (client)

Question 25

``` INFO: The resolver (client) repeats the query until the server is an authority for the name. If the server is the authority for the name, it sends the answer. If it is not, it returns the IP address of the server that it thinks can resolve the query ```

Answer 25

under Iterative solution ----

Question 26

two types of messages (DNS)

Answer 26

query and response

Question 27

_____ consists of a header and question records

Answer 27

query message

Question 28

_____ consists of a header, question recods, answer records, authoritative records, and additional records

Answer 28

response message

Question 29

two types of records that are used in DNS

Answer 29

question records and resource records

Question 30

______ are used in the question section of the query and response messages

Answer 30

question records

Question 31

_______ are used in the answer, authoritative, and additional information sections of the response message.

Answer 31

resource records

Question 32

how are new domains added to DNS? this is done through a ______ a commercial entity accredited by ICANN

Answer 32

registrar

Question 33

____ first verifies that the requested domain name is unique and then enters it into the DNS database. A fee is charged.

Answer 33

registrar

Question 34

T/F The DNS master file must be updated dynamically

Answer 34

True

Question 35

DDNS ( Dynamic Domain Name System )

Answer 35

method to update the DNS master file dynamically

Question 36

T/F | DNS can use either UDP or TCP

Answer 36

true

Question 37

well-know port used by the server

Answer 37

PORT 53

Question 38

____ is used when the size of the response message is less than 512 bytes

Answer 38

UDP

Question 39

If the size of the response message is more than 512 bytes, A __________ is used

Answer 39

TCP Connection