|
61 Which fields
of an IP packet provide for fragmentation of datagrams to allow
differing MTUs in the internet?
A. Identification
B. Flags
C. Frag Offset
D. Type of Service
E. Total Length
Ans A, B & C
The following are the fields in an IP segment, their length, and
their definitions:
VERS (Version number - 16 bits)
HLEN (Number of 32-bit words in the header - 4 bits)
Type of Server (How the datagram should be handled - 32 bits)
Total Length (Total length of header and data - 32 bits)
Identification (Provide fragmentation of datagrams to allow
different MTUs in the internet - 4 bits)
Flags (Provide fragmentation of datagrams to allow different
MTUs in the internet - 4 bits)
Frag Offset (Provide fragmentation of datagrams to allow
different MTUs in the internet - 6 bits)
TTL (Time-To-Live - 6 bits)
Protocol (Upperlayer protocol sending the datagram - 16 bits)
Header Checksum )Integrity check on the header - 16 bits)
Source IP Address (32 bits)
Destination IP Address (32 bits)
IP Options (network testing, debugging, security and others - 4
bits)
Data (4 bits).
62 Which processes does TCP, but not UDP, use?
A. Windowing
B. Acknowledgements
C. Source Port
D. Destination Port
Ans A & B
UDP (User Datagram Protocol) does not use sequence or
acknowledgement fields in transmission.
UDP is a connectionless and unreliable protocol, since there is
no delivery checking mechanism in the UDP data format.
63 What is the UDP datagram format?
A. Source Port - 16 bits, Destination Port - 16 bits, Length
- 16 Bits, Checksum - 16 bits, Data
B. Destination Port - 16 bits, Source Port - 16 bits, Length -
16 Bits, Checksum - 16 bits, Data
C. Source Port - 16 bits, Destination Port - 16 bits, Checksum -
16 Bits, Length - 16 bits, Data
D. Source Port - 8 bits, Destination Port - 8 bits, Length -8
Bits, Checksum - 8 bits, Data
Ans A
The UDP format for a segment is as follows:
Source Port 16 bits
Destination Port 16 bits
Length 16 bits
Checksum 16 bits
Data xx bits
64 What is the function of DDR on Cisco routers?
A. DDR is dial--on-demand routing. It provides a continuous
LAN only connection.
B. DDR is dial-on-demand routing. It provides routing for high
volume traffic.
C. DDR is dial--on-demand routing. It provides a continuous WAN
connection.
D. DDR is dial-on-demand routing. It provides routing for low
volume and periodic traffic.
Answer: D
DDR is dial-on-demand routing. It provides routing for low
volume and periodic traffic. It initiates a call to a remote
site when there is traffic to transmit.
65 What are the two types of access lists that can be
configured on a Cisco router?
A. Standard
B. Extended
C. Filtering
D. Packet
Ans: A & B
The access lists are standard and extended. Standard access
lists for IP check the source address of packets that could be
routed. Extended access lists can check the source and
destination packet plus check for specific protocols, port
numbers, etc.
66 When using access lists, what does a Cisco router check
first?
A. To see if the packet is routable or bridgeable
B. The destination address
C. The source address
D. The packet contents
Ans A
The first thing checked is to see if the packet is routable or
bridgeable. If it is not, the packet will be dropped.
67 How many access lists are allowed per interface?
A. One per port, per protocol
B. Two per port, per protocol
C. Unlimited
D. Router interface +1 per port.
Ans: A
Only one access list is allowed per interface. An access list
must have conditions that test true for all packets that use the
access list.
68 What do the following commands accomplish?
access-list 1 deny 172.16.4.0 0.0.0.255
access-list 1 permit any interface ethernet 0
IP access-group 1 out
A. This will block traffic from subnet 172.16.4.0 and allow all
other traffic.
B. This will allow traffic from subnet 172.16.4.0 and block all
other traffic.
C. All traffic is allowed.
D. All traffic is blocked.
Ans: A
This will block traffic from subnet 172.16.4.0 and allow all
other traffic. The first statement "access-list 1 deny
172.16.4.0 0.0.0.255" will deny access to the subnet 172.16.4.0.
69 What do the following statements in an extended access
list accomplish?
access-list 101 deny TCP 172.16.4.0 0.0.0.255 172.16.3.0
0.0.0.255 eq 21
access-list 101 deny TCP 172.16.4.0 0.0.0.255 172.16.3.0
0.0.0.255 eq 20
access-list 101 permit TCP 172.16.4.0 0.0.0.255 0.0.0.0
255.255.255.255
A. This will block ftp traffic.
B. This will block http traffic.
C. This will permit ftp traffic.
D. This will permit tftp traffic.
Ans: A
This will block ftp traffic since ftp uses ports 20 and 21.
70 Access lists are numbered. Which of the following ranges
could be used for an IP access list?
A. 600 - 699
B. 100 - 199
C. 1 - 99
D. 800 - 899
E. 1000 - 1099
Answer: B & C
AppleTalk access lists use numbers in the 600 - 699 range. IP
uses 1 - 99 for standard access lists or 100-199 for extended
access lists. IPX uses 800 - 899 or 900 - 999 for extended
access lists. IPX SAP filters use 1000 - 1099.
|
