Thứ Ba, 4 tháng 5, 2010

CCNA S2- Version 4.1 Chaper 7 100%

1. A client is communicating with a server on a different segment of the network. How does the server determine what service is being requested by the client?
applies the default service configured in directory services
uses ARP to discover the appropriate service from the local router
sends a request to the client asking for the appropriate service
*identifies the appropriate service from the destination port field

2. What is the function of the TCP three-way handshake?
It enables the synchronization of port numbers between source and destination hosts.
It immediately triggers the retransmission of lost data.
*It synchronizes both ends of a connection by allowing both sides to agree upon initial sequence numbers.
It identifies the destination application on the receiving host.

3. What are three unique characteristics of UDP? (Choose three.)
connection oriented
full-duplex operation
*low overhead
*no flow control
*no error-recovery function
reliable transmission

4. Within TCP, what combination makes up a socket pair?
source port with destination port
source IP address with destination port
source IP address and destination IP address
*source IP address and port with a destination IP address and port

5. What type of update allows client computers to register and update their resource records with a DNS server whenever changes occur?
zone transfer
local recursive query
root domain query
top-level domain query

6. Which DNS zone resolves an IP address to a qualified domain name?
dynamic lookup
forward lookup
resolution lookup
*reverse lookup

7. Which two tasks are the responsibility of the local DNS server? (Choose two.)
maintaining a large number of cached DNS entries
maintaining the ISP server
*mapping name-to-IP addresses for internal hosts
*forwarding name resolution requests to a caching-only server
forwarding all name resolution requests to root servers on the Internet

8. Which protocol is used to send e-mail, either from a client to a server or from a server to another server?

9. A manufacturing company subscribes to certain hosted services from their ISP. The services required include hosted world wide web, file transfer, and e-mail. Which protocols represent these three key applications? (Choose three.)

10. To meet customer expectations, an ISP must guarantee a level of service that is based on what two factors? (Choose two.)

11. Which two statements are true about the OSI and TCP/IP models? (Choose two.)
The two bottom layers of the TCP/IP model make up the bottom layer of the OSI model.
The TCP/IP model is a theoretical model and the OSI model is based on actual protocols.
*The OSI network layer is comparable to the Internet layer of the TCP/IP model.
The TCP/IP model specifies protocols for the physical network interconnection.
*The TCP/IP model is based on four layers and the OSI model is based on seven layers.

12. What type of DNS server is typically maintained by an ISP?

13. Which two options correctly match protocol and well-known port number? (Choose two.)
DNS - 25
FTP - 110
*HTTP - 80
POP3 - 25
*SMTP - 25

14. What are three characteristics of HTTPS? (Choose three.)
It uses a different client request-server response process than HTTP uses.
It specifies additional rules for passing data between the application and data link layers.
*It supports authentication.
It allows more simultaneous connections than HTTP allows.
*It encrypts packets with SSL.
*It requires additional server processing time.

15. User1 is sending an e-mail to What are two characteristics of the process of sending this data? (Choose two.)
It utilizes TCP port 110.
A TCP connection is established directly between the User1 and User2 client computers in order to send the e-mail message.
*It utilizes a store and forward process.
The same application layer protocol is used to send the e-mail and retrieve it from the destination server.
*SMTP is used to send the e-mail message to the mail servers.

16. Which three fields do a TCP header and a UDP header have in common? (Choose three.)
*source port
*destination port
acknowledgment number
sequence number

17. When a host is communicating with multiple applications on the same server at the same time, which two values will likely be the same in all packets for each session? (Choose two.)
*IP address
*MAC address
session number
sequence number

18. What are three characteristics of network reliability? (Choose three.)
*Redundant hardware provides enhanced reliability.
Reliability is measured based on the number of applications in use on the network.
The longer the MTTR, the greater the reliability.
*Fault tolerance is a measure of reliability.
*The longer the MTBF, the greater the reliability.
An ISP guarantees the same level of reliability to all of its customers.

19. Refer to the exhibit. Host1 is in the process of setting up a TCP session with Host2. Host1 has sent a SYN message to begin session establishment. What happens next?
Host1 sends an ACK message to Host2.
Host1 sends a SYN message to Host2.
Host1 sends a SYN-ACK message to Host2.
Host2 sends an ACK message to Host1.
Host2 sends a SYN message to Host1.
*Host2 sends a SYN-ACK message to Host1.

20. Refer to the exhibit. The PC is requesting HTTP data from the server. What is a valid representation of source and destination sockets for this request?
Source - ; Destination -
Source - ; Destination -
*Source - ; Destination -
Source - ; Destination -

21. Refer to the exhibit. Which two statements are true about this file? (Choose two.)
If the gateway address changes, the file will be updated dynamically.
*The command ping fileserv will use IP address
*If the ping command is issued, the file will be checked for the Cisco web server IP address before DNS is queried.
The command ping mypc will use IP address
Name to IP address mappings are added to the file after they are received from DNS.

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