CCENT Review

Put the following descriptions in order from Layer 7 to Layer 1 and give the name of each layer

Layer

Application

Presentation

Session

Transport

Network

Data Link

Physical

Which addresses are valid host IP addresses given the network 172.16.32.8 subnet mask 255.255.255.248?

Which addresses are valid host IP addresses given the network 172.16.32.8 subnet mask 255.255.255.248?

• Shortcut 256-248=8• Range 8 in last octet• 172.168.32.8 – 172.168.32.15

192.168.102.65/2732 hosts on each

subnet192.168.101.64-9573 ok81 ok

192.168.102.97/2732 hosts on each

subnet192.168.101.96-127123 ok148 OUT OF RANGE

• A network host has the IP address 10.250.206.55/20. How many more network devices can be added to this same subnetwork?

• A network host has the IP address 10.250.206.55/20. How many more network devices can be added to this same subnetwork?

• /20 =• 11111111.11111111.11110000.00000000• NOTE - 255.255.XXX.0 (XXX – interesting octet)• 2 ^ 12 = 4096• 4096 – 3 = 4093

To which subnetwork does this packet belong? 10.149.177.135/14

To which subnetwork does this packet belong? 10.149.177.135/14

• /14 subnet mask 255.252.0.0

• 10.149.177.135

• 00001010.10010101.10110001.10000111 AND

• 11111111.11111100.00000000.00000000 EQUALS

• 00001010.10010100.00000000.00000000 binary

• 10.148.0.0 Network

• 10.151.255.255 Broadcast

The router receives a packet with the destination address of 172.16.30.79. To which subnetwork does

this packet belong?

172.16.0.0/21172.16.20.0/21172.16.24.0/21172.16.28.0/21172.16.32.0/21

The router receives a packet with the destination address of 172.16.30.79. To which subnetwork does this packet belong?

/21 = 11111111.11111111.11111000.000000002^3=8

172.16.0.0/21 = 172.16.0.0 – 172.16.7.255172.16.20.0/21 20 not a multiple of 8

172.16.24.0/21 = 172.16.24.0 – 172.16.31.255172.16.28.0/21 28 not a multiple of 8

172.16.32.0/21 = 172.16.32.0 – 172.16.39.255

How many collision and broadcast domains are show in the following network topology?

If all the switches have the default configuration, how many collision and broadcast domains are show in the following network topology?

Collision – 12Broadcast – 3

What is the function of the router in this topology?

What is the function of the router in this topology?

Determines the path to send the message to get to a destination network.Each port, or interface, on a router connects to a different local network. Every router contains a table of all locally-connected networks and the interfaces that connect to them. These routing tables can also contain information about the routes, or paths, that the router uses to reach other remote networks that are not locally attached. When a router receives a frame, it decodes the frame to get to the packet containing the destination IP address. It matches the address of the destination to all of the networks that are contained in the routing table. If the destination network address is in the table, the router encapsulates the packet in a new frame in order to send it out. It forwards the new frame out of the interface associated with the path, to the destination network. Routers contain broadcasts.

Define Default Gateway and discussed how it would be used in this topology.

The default gateway address is the address of the router interface connected to the same local network as the source host.

All hosts on the local network use the default gateway address to send messages to the router.

Once the host knows the default gateway IP address, it can use ARP to determine the MAC address.

The MAC address of the router is then placed in the frame, destined for another network.

• What tables are maintained by routers?

• What tables are maintained by routers?

If the router cannot determine where to forward a message, it will drop it. Configure a routing table with a default route to keep a packet from being dropped. A default route is the interface through which the router forwards a packet containing an unknown destination IP network address.

Identify the following as a unicast, broadcast or multicast.

A company has an 802.11b wireless access point installed. Which type of wireless NIC is a valid standards-based one but will not work in this environment?

A company has an 802.11b wireless access point installed. Which type of wireless NIC is a valid standards-based one but will not work in this environment?

802.11a

Term Definition

Service Set Identifier uses the MAC address to identify which devices are allowed to connect to the wireless network

Extensible Authentication Protocol the user, not just the host, must provide a username and password which is checked against the RADIUS database for validity

Open Authentication used to tell wireless devices which WLAN they belong to and with which other devices they can communicate

Pre-Shared Key wireless devices do not require authentication

Wired Equivalent Privacy generates new, dynamic keys each time a client establishes a connection with the AP

MAC Address Filtering one-way authentication, the host authenticates to the AP, does not authenticate the AP to the host, nor does it authenticate the actual user of the host

WiFi Protected Access uses pre-configured keys to encrypt and decrypt data

Match the wireless term to its definition.

Term Definition

Service Set Identifier uses the MAC address to identify which devices are allowed to connect to the wireless network

Extensible Authentication Protocol the user, not just the host, must provide a username and password which is checked against the RADIUS database for validity

Open Authentication used to tell wireless devices which WLAN they belong to and with which other devices they can communicate

Pre-Shared Key wireless devices do not require authentication

Wired Equivalent Privacy generates new, dynamic keys each time a client establishes a connection with the AP (encrypts)

MAC Address Filtering one-way authentication, the host authenticates to the AP, does not authenticate the AP to the host, nor does it authenticate the actual user of the host

WiFi Protected Access uses pre-configured keys to encrypt and decrypt data

Match the wireless term to its definition.

Once a hacker gains access to the network, what are the four types of threats?

Once a hacker gains access to the network, what are the four types of threats?

• Information theft• Identity theft• Data loss / manipulation• Disruption of service

What command is described below?

• Tests the accessibility of a specific IP address• Sends an ICMP (Internet Control Message

Protocol) echo request packet to the destination address and then waits for an echo reply packet to return from that host

• Output indicates whether the reply was received successfully and displays the round-trip time for the transmissions

What command is described below?Answer - ping

• Tests the accessibility of a specific IP address• Sends an ICMP (Internet Control Message

Protocol) echo request packet to the destination address and then waits for an echo reply packet to return from that host

• Output indicates whether the reply was received successfully and displays the round-trip time for the transmissions

Draw a picture using each of the following cables.

Describe what has to happen for this packet to continue.

Describe what has to happen for this packet to continue.

Describe what has to happen for this packet to continue.

Describe what has to happen for this packet to continue.

Which type of Network Address Translation allows a host on a public

network consistent access to a specified private inside host?

A. Static NAT

B. Dynamic NAT

C. PAT

Which type of Network Address Translation allows a host on a public

network consistent access to a specified private inside host?

A. Static NAT

B. Dynamic NAT

C. PAT

Which addresses are “inside global” addresses?

Which addresses are “inside global” addresses?

Answer - 198.133.219.33 – 198.133.219.62

Which two items are required for initial configuration of Cisco routers if the IOS command-line interface is used

Which two items are required for initial configuration of Cisco routers if the IOS command-line interface is used

Answer – Rollover cable and terminal emulation

Fill in the blanks.

The router bootup process has three stages.

1. Perform _________________________ and load the bootstrap program.

• The _________ is a process that occurs on almost every computer when it boots up. _________ is used to test the router hardware. After _______________, the bootstrap program is loaded.

2. Locate and load the Cisco IOS software.

• The bootstrap program locates the Cisco IOS software and loads it into RAM. Cisco IOS files can be located in one of three places: ____________, _____________, or another location indicated in the startup configuration file. By default, the Cisco IOS software loads from _________ memory. The configuration settings must be changed to load from one of the other locations.

3. Locate and execute the _____________ configuration file or enter setup mode.

• After the Cisco IOS software is loaded, the bootstrap program searches for the ____________ configuration file in NVRAM. This file contains the previously saved configuration commands and parameters, including interface addresses, routing information, passwords, and other configuration parameters.

• If a configuration file is not found, the router prompts the user to enter _______ mode to begin the configuration process.

• If a __________ configuration file is found, it is copied into RAM and a prompt containing the host name is displayed. The prompt indicates that the router has successfully loaded the Cisco IOS software and configuration file.

Fill in the blanks.

The router bootup process has three stages.

1. Perform Power-on self test (POST) and load the bootstrap program.

• The POST is a process that occurs on almost every computer when it boots up. POST is used to test the router hardware. After POST, the bootstrap program is loaded.

2. Locate and load the Cisco IOS software.

• The bootstrap program locates the Cisco IOS software and loads it into RAM. Cisco IOS files can be located in one of three places: flash memory, a TFTP server, or another location indicated in the startup configuration file. By default, the Cisco IOS software loads from flash memory. The configuration settings must be changed to load from one of the other locations.

3. Locate and execute the startup configuration file or enter setup mode.

• After the Cisco IOS software is loaded, the bootstrap program searches for the startup configuration file in NVRAM. This file contains the previously saved configuration commands and parameters, including interface addresses, routing information, passwords, and other configuration parameters.

• If a configuration file is not found, the router prompts the user to enter setup mode to begin the configuration process.

• If a startup configuration file is found, it is copied into RAM and a prompt containing the host name is displayed. The prompt indicates that the router has successfully loaded the Cisco IOS software and configuration file.

• NVRAM – running-config or startup-config• RAM – running-config or startup-config• ROM – running-config or startup-config

• NVRAM – running-config or startup-config• RAM – running-config or startup-config• ROM – running-config or startup-config

Which set of commands is used to name a router

and save the configuration?

Which set of commands is used to name a router

and save the configuration?

Router(config)# hostname South South(config)# exit South# copy running-config startup-config

• A network administrator can ping the Denver router, but gets a 'Password Required but None Set' message when trying to connect remotely via Telnet. Which command or sequence of commands must be applied to the Denver router to allow remote access?

• A network administrator can ping the Denver router, but gets a 'Password Required but None Set' message when trying to connect remotely via Telnet. Which command or sequence of commands must be applied to the Denver router to allow remote access?

• Router(config)# line vty 0 4 Router(config-line)# login Router(config-line)# password cisco

• Which command is used to create an encrypted password that restricts access to the privileged EXEC mode of a Cisco router?

• Which command is used to create an encrypted password that restricts access to the privileged EXEC mode of a Cisco router?

• RouterA(config)# enable secret cisco

• Describe the command ip route 192.168.7.24 255.255.255.248 192.168.7.9?

• What are two ways that TCP uses the sequence numbers in a segment?

• What are two ways that TCP uses the sequence numbers in a segment?

• Missing segments at the destination, reassemble the segments

• Characterize UDP with 3 words. Fill in the blank. UDP is __________________.

• Characterize UDP with 3 words. Fill in the blank. UDP is __________________.

• Connectionless• Faster (fast transport of data at Layer 4)• Dependent (on application layer protocols)• Unguaranteed (works well when an

application does not need guarantee of delivery of data)