February networking question

The February edition of random networking questions.

Another 10 questions to get the grey matter ticking :-)

1. A flat network can be best described as...

A) Physically flat
B) One collision domain
C) One broadcast domain
D) One VLAN

2. Where does routing occur within the DoD TCP/IP reference model?

A. application
B. internet
C. network
D. transport

3. What layer of the OSI model provides the physical transmission of data, handles error notifications, network topology and flow control?

A) Physical
B) Data Link
C) Presentation
D) Session
E) Transport

4. Bridges can only have one spanning tree instance, while switches can have many.

A) True
B) False

5. A Cisco router is booting and has just completed the POST process. It is now ready to find and load an IOS image. What function does the router perform next?

A. It checks the configuration register.
B. It attempts to boot from a TFTP server.
C. It loads the first image file in flash memory.
D. It inspects the configuration file in NVRAM for boot instructions.

6. A CIDR value of /30 equates to what subnet mask?

A) 255.255.255.253
B) 255.255.255.128
C) 255.255.255.248
D) 255.255.255.252

7. What is the maximum size of an Ethernet packet when the frames have ISL tagging?(Include the size of headers and CRC)

A) 64 bytes
B) 1500 bytes
C) 1518 bytes
D) 1522 bytes
E) 1548 bytes

8. Which item represents the standard IP ACL?

A. access-list 110 permit ip any any
B. access-list 50 deny 192.168.1.1 0.0.0.255
C. access list 101 deny tcp any host 192.168.1.1
D. access-list 2500 deny tcp any host 192.168.1.1 eq 22

9. Which two commands correctly verify whether port security has been configured on port FastEthernet 0/12 on a switch? (Choose two.)

A. SW1#show port-secure interface FastEthernet 0/12
B. SW1#show switchport port-secure interface FastEthernet 0/12
C. SW1#show running-config
D. SW1#show port-security interface FastEthernet 0/12
E. SW1#show switchport port-security interface FastEthernet 0/12

10. Which protocol can cause overload on a CPU of a managed device?

A. Netflow
B. WCCP
C. IP SLA
D. SNMP













1. Correct Answer C

A switched network can be described as a flat network because broadcasts are transmitted to every device.

2. Correct Answer B

The picture below shows the comparison between TCP/IP model & OSI model. Notice that
the Internet Layer of TCP/IP is equivalent to the Network Layer which is responsible for
routing decision.

3. Correct Answer B

http://en.wikipedia.org/wiki/Data_Link_Layer

4. Correct Answer A

Bridges are software based and can only have one spanning-tree instance per bridge, while switches are hardware based and can have many.

5. Correct Answer A

Default (normal) Boot Sequence
Power on Router - Router does POST - Bootstrap starts IOS load - Check configuration
register to see what mode the router should boot up in (usually 0x2102 to read startupconfig
in NVRAM / or 0x2142 to start in "setup-mode") - check the startup-config file in
NVRAM for boot-system commands - load IOS from Flash.

6. Correct Answer D

http://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing#Assignment_of_CIDR_blocks

7. Correct Answer E

Cisco's proprietary VLAN tagging (ISL) has a maximum frame size of 1548 bytes.
IEEE 802.1q VLAN tagging has a maximum frame size of 1522 bytes.

8. Correct Answer B

The standard access lists are ranged from 1 to 99 and from 1300 to 1999 so only access
list 50 is a standard access list.

9. Correct Answers C and D

We can verify whether port security has been configured by using the “show runningconfig”
or “show port-security interface” for more detail. An example of the output of “show
port-security interface” command is shown below:

10. Correct Answer D

Sometimes, messages like this might appear in the router console:
%SNMP-3-CPUHOG: Processing [chars] of [chars]
They mean that the SNMP agent on the device has taken too much time to process a
request.

How did you go? very random selection huh :-)

let me know if you found any errors in the comments, more coming .

“Don't cry because it's over, smile because it happened.”

Dr. Seuss

 

Random Cisco based networking questions - CCNA - Part 5

Another half a dozen random networking questions for 2015 with a more routing protocol focus this time, 

enjoy :-).

1. Triggered updates (in a routing protocol) are used to speed the convergence process?

A) True
B) False

2. What class of routing protocol is EIGRP?

A) Link state
B) Distance vector
C) Hybrid

3. What is the administrative distance of OSPF?

A) 110
B) 1
C) 120
D) 90
E) 100

4. What command would you use to erase the startup config of a router?

A) erase nvram
B) erase flash
C) delete startup
D) erase startup
E) delete run

5. What is required for VTP to communicate VLAN information between switches?

A) VTP domain must be identical on all switches
B) One switch needs to be a VTP server
C) A router is required
D) Both A and B are correct
E) None of the above

6. What is the structure of the MAC address?

A) 32 bit network ID + 32 bit host ID
B) 14 bit vendor code + 6 bit serial number
C) 24 bit vendor code + 24 bit serial number
D) Network + Host

Searching for what type of nic card you have in your PC? The easiest way is with the MAC address ( not the kind shown below :-)

A great link you should bookmark for Vendor/Ethernet/Bluetooth MAC Address Lookup and Search at MACFIND.  This allows you to match your MAC address to its vendor or a vendor to a MAC - I find it very useful :-).

http://www.coffer.com/mac_find/

1.  Answer A

A triggered update is sent immediately in response to a change in the network (e.g. A link going down). The router detecting the change immediately sends an update message to its adjacent routers, which then generate their own triggered updates. This process continues until the network converges. Triggered updates occurs independently from the regular routing updates and are intended to speed the convergence process.

2. Answer C

EIGRP is a hybrid routing protocol which uses a combination of distance vector and link state methods to determine the best path. EIGRP is considered an advanced distance vector protocol because EIGRP sends out only incremental updates.

3. Answer A

Administrative distance is used by Cisco routers to select the best path when there are two or more different routes to the same destination from two different routing protocols. Administrative distance defines the reliability of a routing protocol.

Routing Protocol	Administrative distance
Directly connected interface	0
Static route out an interface	1
Static route to next-hop address	1
DMNR - Dynamic Mobile Network Routing	3
EIGRP summary route	5
External BGP	20
Internal EIGRP	90
IGRP	100
OSPF	110
IS-IS	115
Routing Information Protocol (RIP)	120
Exterior Gateway Protocol (EGP)	140
On Demand Routing (ODR)	160
External EIGRP	170
Internal BGP	200
Floating Static Route (ex. DHCP-learned)	254
Unknown	255

(Note : An AD of 255 will cause a router to dump this route from its table)

4. Answer D

To erase the startup configuration use the following command:

Router#erase startup-config, or
Router#erase startup

5. Answer D

VTP requires the following to communicate VLAN information between switches.  The VTP domain must be identical on all switches and one switch needs to be a VTP server.

6. Answer C

MAC Addresses are 48 bits long and consist of a 24 bit vendor code and a 24 bit serial number.

More coming, please leave comments if you find any errors or want to debate an answer :-)

A new series of Cisco base networking questions for 2014 - part 6

Lets get to thinking with a random selection of Networking / IT based questions and answers :-)








1. When each network segment uses a different subnet mask this is referred to as...

A) Classful routing
B) Classless routing

2. What is the structure of the MAC address?

A) 32 bit network ID + 32 bit host ID
B) 14 bit vendor code + 6 bit serial number
C) 24 bit vendor code + 24 bit serial number
D) Network + Host
3. Which WAN protocol is capable of carrying video, Circuit Switched Data And Telephone Services using normal phone network?

A) Frame Relay
B) ISDN
C) PPP
D) ISL

4. What do the IOS commands below achieve?

Router(config)#access-list 5 permit 172.5.15.2
Router(config)#line vty 0 4
Router(config-line)#access-class 5 in
 A) Create an extended ACL to only permit host 172.5.15.2 to connect to VTY
B) Create a standard ACL to only permit host 172.5.15.2 to connect to VTY
C) Create an extended ACL to only permit hosts on the network 172.5.15.2 to connect to VTY
D) Create a standard ACL to only permit hosts on the network 172.5.15.2 to connect to VTY

5. What OSI layer does the following refer to?

"Establishes availability of intended communication partners, establishes agreement on procedures regarding error recovery and data integrity and synchronizes networked applications"

A) Transport layer
B) Session layer
C) Datalink layer
D) Application layer
E) Presentation layer

6. IGRP advertises routes to interior, system and exterior routes

A) True
B) False




-->
Clickbank Products



1. Correct Answer B

http://en.wikipedia.org/wiki/Classful_network

2. Correct Answer C

MAC Addresses are 48 bits long and consist of a 24 bit vendor code and a 24 bit serial number.

3. Correct Answer B

ISDN (Integrated Services Digital Network) is a set of standards for simultaneous digital communications (voice, video, data) over the traditional circuits of the public switched telephone network.

4. Correct Answer B

Router(config)#access-list 5 permit 172.5.15.2
Router(config)#line vty 0 4
Router(config-line)#access-class 5 in

This standard access list permits only the host 172.5.15.2 to connect to your VTY telnet line.

5. Correct Answer D

The Application layer of the OSI model (layer 7) establishes availability of intended communication partners, establishes agreement on procedures regarding error recovery and data integrity and synchronizes networked applications.

6. Correct Answer A

IGRP advertises three types of routes:

Interior routes are routes between subnets in the network attached to a router interface.
System routes are routes to networks within an autonomous system.
Exterior routes are routes to networks outside the autonomous system.

Let me know how you went, :-)

 "I couldn't wait for success so I started without it" 

Jonathan Winters

A new series of Cisco base networking questions for 2014 - part 5

Another selection of random Networking / IT based questions and answer, hopefully to help with getting your certifications or just increase knowledge - enjoy. 



1.  Which of the following best describes the presentation layer?

A) Translates between different data formats
B) Provides transport services
C) Supports communication between different programs
D) Establishes and terminates applications

2. Which protocol is used to determine the IP address if the MAC address is already known?

A) ARP
B) RARP
C) IP
D) IPX
E) TCP

3. What IOS command will copy the current running-config to NVRAM?

A) write memory
B) wr nvram
C) copy start-up run
D) copy run start
E) Answers A and D are correct

4. What process is used to check whether packets have been received when using IP?

A) Acknowledgments
B) CRC
C) Windowing
D) Flow control
E) None

5. Subnetting Questions

    a. What is the broadcast address of the network 192.168.98.64/26? 

    b. Which subnet does host 172.27.249.128 255.255.248.0 belong to?

6. What IOS command would you issue in privileged-mode to change the router configuration stored on TFTP?

A) config t
B) config mem
C) config net
D) config tftp










1. Correct Answer A

Presentation Layer is the 6th Layer of OSI model. It is responsible for converting different formats to device understandable language at both ends.

 2. Correct Answer B

Reverse Address Resolution Protocol (RARP) is a networking protocol used by a host computer to request its IP address from an administrative host, when it knows its MAC address.
 http://en.wikipedia.org/wiki/Reverse_Address_Resolution_Protocol 

 3. Correct Answer E

There are two types of configuration files on a router:

Running config - The configuration currently running on the router. Stored in RAM.
Startup config - Saved configuration stored in NVRAM.

To save the running configuration to the startup configuration use the following command.

Router# copy running-config startup-config  
or
Router# copy run start

 4. Correct Answer E

Trick question. IP provides no form of error correction / acknowledgements.
(Cisco loves trick questions....)

 5. Correct Answers

 a.  192.168.98.127
 b.  172.27.248.0

6.  Correct Answer C

To change the router configuration stored on TFTP you use configure network (config net)


 A couple of curly ones there, subnetting always seems to slow one down :-)

Stay tuned for more...

A new series of Cisco base networking questions for 2014 - part 4

Another selection of random Networking / IT based questions and answers to get the grey matter ticking..enjoy

1. What is the correct sequence of Spanning Tree states?

A) Blocking, Listening, Learning, Forwarding, Disabled
B) Disabled, Blocking, Listening, Learning, Forwarding
C) Learning, Listening, Forwarding, Disabled, Blocking
D) Listening, Learning, Forwarding, Blocking, Disabled

 2. What type of NAT allows you to map multiple unregistered IP addresses to a single registered IP address?

A) Static NAT
B) Dynamic NAT
C) Overloading (Port Address Translation)

3.  You are having to enter a certain command into the router several times, how would you recall the last entry?

A) Up arrow
B) Down arrow
C) Ctrl+N
D) Shift-P
E) Alt-P

 4. What is responsible for ensuring a router is functional and the interfaces are present on booting?

A) Bootstrap
B) POST
C) ROM monitor
D) NVRAM
E) Configuration register

5.  What is the Spanning Tree forward delay?

A) The time that is spent in the Listening and Learning states
B) 50 seconds
C) Time taken for a switch to go from Listening to Forwarding
D) Time taken for a switch to go from Blocking to Forwarding


6. What describes the role of the Session layer?

A) Provides transport services
B) Translates between different data formats
C) Supports communication between applications
D) Establishes and terminates communications between applications 







1,  Correct Answer A

STP switch port states:

Blocking
Listening
Learning
Forwarding
Disabled

2. Correct Answer C

 PAT (Port Address Translation) allows you to map multiple unregistered IP addresses to a single registered IP address

3. Correct Answer A

Cisco Keyboard Shortcut Actions

Up Arrow Displays your previous commands.  (command history)
TAB Key Completes a partially typed CLI commands.
CTRL+Z Takes you back to Privileged EXEC Mode.

CTRL+A Places the cursor at the beginning of a line.
CTRL+E Places the cursor at the end of a line.
CTRL+R Redisplays the current command line.
CTRL+W Erases a word (behind the cursor).
CTRL+U Erases an entire line.

4. Correct Answer B

POST (Power-on-self-test) stored in ROM performs a basic router health-check on booting.

5. Correct Answer A

Forward delay — The time that is spent in the listening and learning state, 15 sec by default, but you can tune the time to be between 4 and 30 sec.

6. Correct Answer D

The Session Layer (layer 5) of the OSI model provides the mechanism for opening, closing and managing a session between end-user application processes.

Very random I know, how did you go? More to come, fun isn't it :-)

Courage doesn't always roar. Sometimes courage is the quiet voice at the end of the day saying, "I will try again tomorrow."
~ Mary Anne Radmacher "

A new series of Cisco base networking questions for 2014 - part2

A set of questions for those interested in IT / networking / certification or just generally curious  - Enjoy.

(This time with some IPv4 questions thrown into the mix :-)

The secret of life is not to do what you
like but to like what you do.
By: Anonymous

1. What will be the IP address of the second subnet given the following?

172.16.0.0 255.255.224.0 (Assume ip subnet-zero is enabled)

A) 172.16.0.0
B) 172.16.8.0
C) 172.16.16.0
D) 172.16.32.0
E) 172.16.64.0

2. What is the maximum number of subnets and hosts per subnet achievable from the network 172.22.0.0 255.255.255.224?

A) 2048 subnets and 30 hosts
B) 256-224=32 ip per subnet - 30 hosts
C) 256/32=8 subnets per 4th octet
D) 256 x 8 = 2048 total subnets for B class address


3. What are the 3 ways of assigning a switched port to VLANs?

A) Switch-centric, Port-centric, Dynamic VLANs
B) Port-centric, Static VLANs, Dynamic VLANs
C) Interface-based, Static VLANs, Dynamic VLANs

4. What is the default time BPDUs are sent and received by switches?

A) 2 seconds
B) 10 seconds
C) 30 seconds
D) 60 seconds

5. What does Router(config)# no access-list 1 command achieve?

A) Removes Access List 1
B) Disables ACL on interface 1
C) Nothing, this is not a Cisco command









1. Correct Answer: D 

The subnet block size is 256 - 224 = 32
The first subnet will be subnet zero 172.16.0.0
The second subnet will be 172.16.32.0

2. Correct Answer: A

2048 subnets and 30 hosts

3. Correct Answer: B

Three ways of assigning a switched port to VLANs:

Port-Centric - All nodes connected to ports in the same VLAN are assigned to the same VLAN ID.
Static VLANs - Statically assign ports to a VLAN.
Dynamic VLANs - Ports that can automatically determine their VLAN assignments based on MAC addresses.

4. Correct Answer: A 

The Spanning Tree Protocol (STP) is a network protocol that ensures a loop-free topology for any bridged Ethernet local area network. The basic function of STP is to prevent bridge loops and the broadcast radiation that results from them. Spanning tree also allows a network design to include spare (redundant) links to provide automatic backup paths if an active link fails, without the danger of bridge loops, or the need for manual enabling/disabling of these backup links.

The bridges have to determine the root bridge and compute the port roles (root, designated, or blocked) with only the information that they have. To ensure that each bridge has enough information, the bridges use special data frames called Bridge Protocol Data Units (BPDUs) to exchange information about bridge IDs and root path costs.

A bridge sends a BPDU frame using the unique MAC address of the port itself as a source address, and a destination address of the STP multicast address 01:80:C2:00:00:00.

There are two types of BPDUs in the original STP specification (The Rapid Spanning Tree (RSTP) extension uses a specific RSTP BPDU.[4]):

Configuration BPDU (CBPDU), used for Spanning Tree computation
Topology Change Notification (TCN) BPDU, used to announce changes in the network topology
BPDUs are exchanged regularly (every 2 seconds by default) and enable switches to keep track of network changes and to start and stop forwarding at ports as required.

5. Correct Answer: A

"No" is generally used in front of Cisco config lines to remove them from configuration, in this case No Removes Access List 1

More questions Coming - see you soon...

Sign up to get them in your email 

A new series of Cisco base networking questions for 2014 - part1

Here are a number of random questions based on the Cisco certifications, but they relate to IT and networking in general as well. See how you go and check last years series for more!

(Some of these are a little tricky, just like the cert exams :-)

Action may not always bring happiness...
but there is no happiness without action.
By: Benjamin Disraeli

1. What is true about the MAC address?

A) Used to identify networks
B) Defined at the Network layer
C) Unique for every networked device in the world
D) Identical to the IP address

2. Bridges cannot provide congestive feedback information to end nodes?

A) True
B) False

3. What do asymmetric switches require?

A) memory buffers
B) extra ports
C) statically assigned ports only
D) high speed CAM

4. The Cisco Spanning Tree protocol is compatible with IEEE 802.1d?

A) True
B) False

5. What is the administrative distance of EIGRP?

A) 110
B) 1
C) 120
D) 90
E) 100

6. What IOS command would disable CDP on a routers interface?

A) no cdp enable
B) disable cdp
C) no cdp
D) no cdp run

7. Bridges forward layer 2 broadcasts, but switches don't.

A) True
B) False

8. Router>     What mode are you in when you see this prompt?

A) user exec mode
B) privileged mode
C) global configuration mode
D) interface configuration mode
E) routing protocol configuration

9. What layer of the OSI model is responsible for multiplexing upper-layer applications, establishing sessions and tearing down virtual circuits?

A) Presentation
B) Session
C) Transport
D) Network
E) Data Link

10. What is port 53 used for?

A) FTP data
B) FTP program
C) Telnet
D) DNS
E) TFTP

/center>

Answers to the above questions..

1. Correct Answer: C

MAC addresses are assigned by the manufacturer of a network interface card (NIC) and are stored in its hardware. A MAC address contains the manufacturer's identification number.
The MAC address may also be referred to as the burned-in address, hardware address, Ethernet address or physical address and is part of the Data Link layer, specifically the Media Access Control sub-layer of the Data Link layer.

2. Correct Answer: A

Flow Control and Congestive Feedback are functions of the Network layer. Bridges operate at the Data Link layer so these responsibilities fall to the end devices in a bridged environment.

3. Correct Answer: A

With ability for support of high bandwidth ports Asymmetric Switches require more Buffer memory for storing & forwarding of packets for fast processing.

4. Correct Answer: B

The original Spanning-Tree protocol was created by Digital Equipment Corporation (DEC) which is now part of Compaq. The IEEE created its own version called IEEE 802.1d which is not compatible with the original version. Cisco enhanced the original 802.1d specification with features such as Uplink Fast, Backbone Fast, and Port Fast to speed up the convergence time of a bridged network. However these new features are proprietary, and can only be configured on Cisco switches.

5. Correct Answer: D

Administrative distance is used by Cisco routers to select the best path when there are two or more different routes to the same destination from two different routing protocols. Administrative distance defines the reliability of a routing protocol. EIGRP has an administrative distance of 90.

6. Correct Answer: A

You can disable CDP on an interface which supports CDP with the no cdp enable command.

7. Correct Answer: B

Both switches and bridges forward layer 2 broadcasts.

8. Correct Answer: A

Here is a summary of Cisco IOS router command prompts:

Router> - User EXEC mode
Router# - Privileged EXEC mode
Router(config)# - Global configuration mode
Router(config-if)# - Interface level configuration mode
Router(config-router)# - Routing engine level within configuration mode
Router(config-line)# - Line level (vty, tty, async) within configuration mode

9. Correct Answer: C

The Transport layer is responsible for multiplexing upper-layer applications (ports), establishing sessions and tearing down virtual circuits.

10. Correct Answer: D

DNS uses commonly known port 53

Stay tuned for more questions ...

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Cisco Exam Demo

Are you considering getting Cisco certified? 

A lot of Cisco students attempting the CCNA exams fall into a trap. They learn the theory and a little bit of troubleshooting, but they have no idea what the CCNA exam will be like when they go to the testing center.

Luckily Cisco have a little known demo which shows you what types of questions you will encounter on the exam and lets you try them out. Once you are familiar with the different types of exam questions, you'll be much more confident going into the exam.

Go to the Cisco Exam demo

To your success..

Contemplating a career in Information Technology?

It's not easy trying to get your first job in IT, you have to compete against candidates who have years of experience. However many of these experienced candidates don't have certifications or a college degree to back up their on-the-job experience, as an older IT professional I find myself in this category.

Unfortunately it is an employers market, where they can pick and choose who they hire. IT graduates sometimes find themselves in a catch 22 position where they can't get a job without experience without getting a job in the first place.

However, a good certification such as the CCNA and a relevant college degree is still the best way to position yourself for your future career, or to expand your career as I am doing.

Certifications provide you with some hands-on configuration experience that will be a step in the right direction to getting the experience you need, however in order to get the commercial experience employers want, you'll have to start from the bottom and work your way up to those high-paying IT positions.

Remember that employers generally like to promote from within their company, so don't be disheartened if you have to start in an entry-level help desk position. Remember nobody starts out at the top. Work hard and seek the promotion when it becomes available.

If an employer offers a 6-month contract don't dismiss the opportunity to show your worth. If you are good they are likely to employ you on a full-time basis when the contract ends.  The same goes for temporary roles, try and get your foot in the door and impress.

Don't forget the local computer support companies. These companies can provide you with invaluable experience and their hiring requirements are generally less than big corporations. You my even find that they are willing to sub-contract jobs to workers.

Non-profit organizations such as churches and charities need IT support too, and volunteering is another route to getting valuable experience. This will look great on your resume and hopefully you'll get glowing references too.

Craft a resume that doesn't sell yourself short, you want your resume to stand out from the crowd. Include all your relevant IT skills and emphasize industry buzzwords that employers are asking for on job adverts if you have those skills. Add any relevant experience with certain technologies should be added.

Remember, you may not have a wealth of experience that other job candidates have, but this is only one attribute employers look for. If you can demonstrate your professionalism, passion for technology as well as being able to communicate as well as relevant qualifications you will eventually succeed in breaking into IT.

Good luck in your job search and career in information technology.