Discovery II Semester Review 1. What is the purpose of PAT? Used when a company needs a system that allows simultaneous access to the internet for many users and the company only have a few public IPs 2. What address is used in an IPv4 environment to forward packets. Destination IP address

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Discovery II Semester Review


1.

What is the purpose of PAT?

Used
when a company

needs a system that allows simultaneous access to the internet for man
y

users and
the company only have a few public IPs


2.

What address is used in an IPv4 environment to for
ward packets.

Destination IP address


3.

What does copy tftp running
-
config do?

Copies the configuration file from a server to RAM

(not NVRAM

it is only stored in NVRAM via the
copy run start)




4.

You are adding a new network.
What 3 tasks (configur
ations) must be completed
to configure new
interface and
implement dynamic IP routing.

1. Select a routing protocol


various ones to choose from (RIP, EIGRP, OSPF)

2.
Assign an IP address and subnet mask to the interface

3.
Configure the routing protoc
ol with the new network IP address


5.

How many hosts addresses are there when using 130.68.0.0 with a subnetmask of 255.255.248.0.

11111111.11111111.11111000.00000000 2 to 11 (host addresses are represented by zeros) = 2048 total
but cannot use two of
them so 2046.


6.

What is the purpose of the TCP three
-
way handshake?

Synchronizing sequence numbers between source and destination in preparation for data transfer.



7.

How do port
filtering

and access lists help provide network security?

They prevent sp
ecified types of traffic from reaching specified network destinations.



8.

What is the difference between NAT and PAT?

PAT is basically NAT but overloaded. PAT uses unique source port numbers to distinguish between
translations.


9.

What application laye
r protocol is used to gather data about network performance.


SNMP

SNMP is a network management protocol that enables network administrators to gather data about the
network and corresponding devices. SNMP management system software is available in tools s
uch as
CiscoWorks


10.

What is the most commonly used exterior routing protocol.

B
order
G
ateway
P
rotocol
--

BGP



95%



11.

What are commands required to configure passwords on a router

or switch



the console password,
the enable password, the secret passwo
rd and the vty passwords.


MOST IMPORTANT ONES TO SET ARE CONSOLE AND VTY


DON’T WANT ANYONE
WALKING UP TO THE CONSOLE AND BEING ABLE TO TELNET.


Console:

Router(config)#line console 0

Router(config
-
line)#password [password]


Router(config
-
line)#login

VTY
:

Router(config)#line vty 0 4

-

on a switch vty 0 15

Router(config
-
line)#password [password]


Router(config
-
line)#login

Enable:

Router(config)#
enable password
[password]

Secret:

Router(config)#
enable secret
[password]


Router(config)#
service password
-
encryption


12.

What are the default subnet masks for all three classes


a, b, c

A


255.0.0.0

B


255.255.0.0

C


255.255.255.0


13.

What does a routing protocol use to determine the best path.


Metric (which includes various things)


14.

What is the pur
pose of the routing process.


To
select paths that are used to direct traffic to destination networks


15.

What type of cable is used to connect a PC to a switch.


straight through


16.

What are 3 characteristics of TCP protocol. How does TCP ensure deliv
ery?



Reliable



Flow control (using windows/SYN)



Requires more bandwidth and overhead than UD
P



Creates a virtual session between end
-
user applications



Responsible for breaking messages into segments and reassembling them at their destination

(using
sequence
#s)



Forced retransmissions of

unacknowledged packets


Acknowledgments

and sequence #s


17.

What typ
e of address is 192.168.17.111
/28
--

a host, a network, a broadcast, a multicast?

THIS IS A BROADCAST ADDRESS


Class C


192

So /28 is 11111111.11111111.1
1111111.11110000.

Lowest bit borrowed is 16 so networks are jumping by 16

Network

range


broadcast

.0


.1
-
.14


.15

.16


.17
-
.30


.31

.32


.33
-
.46


.47

.48


.49
-
.62


.63

.64


.65
-
.78


.79

.80


.81
-
.94


.95

.96


.97
-
.110

.111

.112


.113
-
.126

.127

.128


.127
-
.142

.143


18.

What does debug ip rip do? Why does one use it sparingly?

displays RIP routing activity in real time

takes up a lot of processor usage so use only when necessary


19.

Describe the bottom up approach to troubleshooting.


Start with the lowes
t level of the OSI layer

and work up through the layers

check cables, then nic, then IP
settings


20.

If FTP is the only application not working for a customer, what would you suspect is the problem?


Check the firewall
-

Firewalls often do not permit acti
ve FTP connections to hosts located on the inside
network.


21.

What protocol should be used to transfer credit card info. from customers to company’s web server.


HTTPS


22.

What are two purposes of DNS?

To resolve human
-
readable domain names to numeric I
P addresses

Replace static HOSTS file with a more practical dynamic system


23.

How does a router know of paths to a destination network?


Manually configured routes
--

static

Updates from other
r
outers

--

dynamic


24.

What two protocols allow network dev
ices to report their status and events to a
centralized

network
management device?

Syslog and SNMP


25.

When
credit

card purchases are made and it uses a modem to transfer the transaction to the central
office, what type of WAN serial connection is in use?

Leased, packet or
circuit switched
, point
-
to
-
point.


Circuit switched


three types of serial WAN connections.


Point
-
to
-
Point

-

A point
-
to
-
point WAN connection is a predefined communications path from the customer
premises through a telecommunications se
rvice provider (TSP) network. Point
-
to
-
point lines are
usually
leased

from a TSP. These lines are often called leased lines. Point
-
to
-
point connections are typically the
most expensive

of the WAN connection types and are
priced based on bandwidth required
and distance
between the two connected points
.


Circuit Switched

-

A circuit switched connection functions
similar
ly
to

the way
a phone call

is made over a
telephone network. When making a phone call to a friend, the caller picks up the phone, opens the ci
rcuit,
and dials the number. The caller hangs up the phone when finished and the closes the circuit. An example
of a circuit switched WAN connection is an ISDN or
dial
-
up connection
.


Pack
et Switched
-

In a packet switched WAN connection, networks have con
nections into the TSP
switched network. Many customers share this TSP network.
Instead of the circuit being physically reserved
from source to destination
, as in a circuit switched network. Each
customer has their own virtual circuit
. A
virtual circuit is
a
logical path between the sender and receiver
, not a physical path. An example of a packet
switched network is
Frame Relay
.


26.


A small tire retailer
requires

a
low
-
cost WAN

connection to their headquarters to manage its inventory and
process customer
sales in real time. Which WAN connecti
on would be best suited? Sonet,

T3, dialup,
DSL
, leased?




27.

Why are port number
s

in a TCP header of a segment important?


So that the data is used with the appropriate application


28.

About a minute after a swi
tch has started, the SYST LED on the front of the switch transitions from
blinking green to amber. What is the meaning of the amber LED?


Switch has failed POST and must be sent for service.


29.

What is the difference between an IDS and IPS (security sol
utions)


An intrusion detection system (
IDS
) is a
software
-

or hardware
-
based solution

that passively listens to
network traffic.
Network traffic does not pass through an IDS device
. Instead, the IDS device monitors
traffic through a network interface. Whe
n the IDS detects malicious traffic, it sends an alert to a
preconfigured management station.


An intrusion prevention system (
IPS
) is an active
physical device

or software feature.
Traffic travels in one
interface of the IPS and out the other
. The IPS
exa
mines the actual data packets

that are in the network
traffic and works in real time to permit or deny packets that want access into the network