Networking Questions 2016 Part 5

Here are some more very random networking questions based around the CCNA type of exam head scratchers... :-)

1. 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)

2. Each port on a switch is a separate broadcast domain?

A) True
B) False

3. Inter-Switch Link and IEEE 802.1Q are types of...

A) Spanning Tree Protocol
B) Trunking method
C) Ethernet
D) Routing protocol

4. What statement is not correct when talking about a shared-medium Ethernet LAN?

A) The data frame broadcast delivery nature of Ethernet can have a negative affect on performance
B) Adding repeaters and hubs to an Ethernet network can increase latency
C) Ethernet is a best-effort delivery service
D) Collisions are caused by CSMA/CD on an Ethernet network

5. What TCP/IP layer are TCP and UDP protocols associated with?

A) Application
B) Host-to-Host
C) Internet
D) Network Access

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

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









1. Answer: C

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

2. Answer: B

Switches create separate collision domains but a single broadcast domain.

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

3. Answer: B

Both Inter-Switch Link and IEEE 802.1Q are types of VLAN identification.  Inter-Switch Link (ISL) is a Cisco proprietary protocol whereas IEEE 802.1Q is a standard method of frame tagging.
4. Answer: D (did you get the "not"?)

Carrier Sense Multiple Access / Collision Detection (CSMA/CD) is a set of rules determining how network devices should respond when two devices try to use the shared medium simultaneously.

http://en.wikipedia.org/wiki/Carrier_sense_multiple_access_with_collision_detection
5. Answer: B

TCP and UDP protocols are associated with the Transport layer of the TCP/IP model, which is sometimes referred to as the "host-to-host transport layer".

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

Internet protocol suite examples:
Application layer
BGP · DHCP · DNS · FTP · HTTP · IMAP · LDAP · MGCP · NNTP · NTP · POP · ONC/RPC · RTP · RTSP · RIP · SIP · SMTP · SNMP · SSH · Telnet · TLS/SSL · XMPP ·
Transport layer
TCP · UDP · DCCP · SCTP · RSVP 
Internet layer
IP  (IPv4 · IPv6) · ICMP · ICMPv6 · ECN · IGMP · IPsec  
Link layer
ARP · NDP · Tunnels  (L2TP · PPP · MAC  (Ethernet · DSL · ISDN · FDDI ·

6. Answer: C

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


More random question coming soon :-)

   “Employ your time in improving yourself by other men's writings, so that you shall gain easily what others have labored hard for.”

? Socrates

IPV4 Subnetting Tips

It always takes a bit to get your head around subnetting for the first time, and even more to answer the exam questions they give as they often are designed to trick you.

For random IPV4 subnetting questions to hone your skills, I suggest you bookmark:

http://www.subnettingquestions.com/

Memorizing the tables help immensely,  although at first appearance they appear daunting.

/24	8	255.255.255.0	256 = 28	Large LAN
/25	7	255.255.255.128	128 = 27	Large LAN
/26	6	255.255.255.192	64 = 26	Small LAN
/27	5	255.255.255.224	32 = 25	Small LAN
/28	4	255.255.255.240	16 = 24	Small LAN
/29	3	255.255.255.248	8 = 23	Smallest multi-host network
/30	2	255.255.255.252	4 = 22	"Glue network" (point to point links)
/31	1	255.255.255.254	2 = 21	Point to point links (RFC 3021)
/32	0	255.255.255.255	1 = 20	Host route

TIPS:

Remember the binary number doubles for each bit.  2, 4, 8, 16, 32, 64, 128, 256 etc

Also remember 8, 16, 24, 32 for the 8 bit block sizes. 

To find the block size, find the first octet that is not 255, then subtract it from 256... eg subnet mask of 255.255.255.224 ...256 - 224 = block size of 32 

Subtract 2 from the block size to get the number of hosts eg 32 - 2 = 30 host IP.
(network and broadcast addresses cannot be used for user IP)

For the slash format, eg /27 subtract 27 from 32 to give a remainder of 5
Then if we count up 5 times doubling, 2, 4, 8, 16, 32 we get to the same block size of 32.

We also see that 224 is equal to 3 subnet bits taken from the octet ( 11100000) in a C class subnet, this will equal 8 subnets (allowing for subnet zero) 1, 2, 4 = 7+1 = 8 subnets.


Some providers have questions relating to old routing kit that did not allow the use of the all "1" subnet or all the "0" subnet (known as 'subnet zero').On all new Cisco routers, the number of subnets is calculated using the formula of 2^n by default. However, for legacy routers network engineers use 2^n - 2 to comply with the almost obsolete RFC 1878 standard. 

Some text books and courses that relate to old routing equipment also refer to the old formula as do some Microsoft Learning courses. If you're planning to take a non-Cisco exam that involves subnetting you should make sure you understand the 'subnet zero' concept' and check what is considered the default correct formula by your examining board

Once you get the patterns 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, etc and the masks 255, 254, 252, 248, 240, 224, 192, 128 burnt in it will become way easier :-)

Networking Questions 2016 Part 4

Been a while since we've stretched the grey matter, time to get to some more thinking with these random networking questions :-) Have fun.


1. In which layer of the OSI model does framing occur?

A) Layer 3
B) Physical layer
C) Application layer
D) Layer 2
E) Network layer

2. How would you view the current Cisco Configuration Register value?

A) show config-register
B) show reg
C) show config
D) show version

3. What does 'r' stand for in the capabilities of a Cisco device in the output of a show cdp neighbor command?

A) Repeater
B) Router
C) IGMP
D) Host
E) Switch

4. Ethernet technology relates to which type of network?

A) WAN
B) LAN
C) MAN
D) SAN
E) All of the above

5. What is the numerical value of the Bridge Priority held by Catalyst switches?

A) 32500
B) 32768
C) 100
D) 1024
E) 32700

6. 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

7. PPP can be used over what types of serial connections?

A) Synchronous
B) Asynchronous
C) Both
D) Neither

8. Which of the following could be a valid MAC address?

A) 00-08-74-CE-B7-90
B) 192.168.0.1
C) FFFF.FFFF.FFFF.FFFF
D) 255.255.255.240




-->
Clickbank.com Ads





1. Answer: D

The protocol data unit (PDU) of the Data Link layer (Layer 2) is the frame.  Data passed down from the Network layer is framed at layer 2 before being sent on to the Physical layer.

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

2. Answer: D

You can see the current value of the configuration register by using the show version command.
eg:
Configuration register is 0x2102


3. Answer: A

 Router#show cdp neighborsCapability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge                  S - Switch, H - Host, I - IGMP, r - Repeater

 4. Answer: B

The IEEE standards relating to Ethernet technology were originally developed for local area networks.
This is the Cisco definition, although in practice this definition is very blurred :-).

 5. Answer: B

The Bridge Priority is the numerical value held by switches. All Catalyst switches have a default priority of 32768. To determine the root bridge you combine the priority of each bridge with its MAC. If two switches have the same priority value the lowest MAC address becomes the root bridge.

6. 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.

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


7. Answer: C 

Point-to-Point Protocol (PPP) can be used over ISDN (synchronous) and dial-up (asynchronous) connections.

8. Answer: A

The standard format for printing MAC addresses is six groups of two hexadecimal digits, separated by hyphens (-) or colons (:) e.g. 00-08-74-CE-B7-90, 00:08:74:CE:B7:90.
Another convention commonly used is three groups of four hexadecimal digits separated by dots e.g. 0573.4567.19ab.

How did you go??

I told you they would be random, more coming, stay tuned.

Octopod, the new kind of robot.

Overwatch Animated Short | "The Last Bastion" (AU)

Cisco CLI Analyzer 2.0 Released - IOS and NX-OS support added!

Cisco CLI Analyzer 2.0 Powered by TAC What's New? New name: Now that we support IOS and NX-OS the ASA CLI Analyzer is now the "Cisco CLI Analyzer".   Note: If you currently use Output Interpreter please migrate over to CLI Analyzer as it has more advanced diagnostic capabilities. Enhancements:   Advanced System Diagnostics for IOS, IOS-XE, IOS-XR. XR includes "Virtual TAC" providing deep diagnostics and customized analysis. New Contextual Help & Highlighting and System Diagnostic checks added! Platform Contextual Help & Highlighting System Diagnostics ASA 651 131 IOS, IOS-XE 705 221 IOS-XR 6,201 119 NX-OS 250 N/A •Device detection: Information such as serial #, software version, model and device type are automatically added to Cisco supported devices (ASA, IOS*, NX-OS) within the Devices tab. •Contextual Menu: Added the ability to highlight text in the CLI and search cisco.com •Request new CHH content •Keyboard shortcuts: Tab through your sessions (CTRL+Tab), open a new session (ALT+Q) and Search Highlight (CTRL+F) Security: Save CCO credentials using Master Password. Overview: In this release of Cisco CLI Analyzer 2.0 we added advanced TAC tools and knowledge to support IOS, IOS-XE, IOS-XR, NX-OS and new ASA content. UCS tools and advanced Case automation capabilities are in the pipeline! What's next?    Upgrade to 2.0 now!  The Cisco CLI Analyzer is your ticket to the most current and powerful tools from Cisco TAC.   Free Cisco labs for CCNA, CCNP and CCIE students! Presented by René Molenaar - CCIE #41726

 
 

Networking Questions 2016 - Part 3

The next installment of Six more random networking questions for your enjoyment :-)


1.  When STP is converging no data can move through the switched network.

A) True
B) False

2. What should be carried out within the Cisco hierarchy at the distribution layer?

A) ACL
B) Security and network policies
C) VLANs
D) WAN access
E) All of the above

3. What protocol range would you use for IP in ACLs?

A) 1-99
B) 800-899
C) 200-299
D) 1000-1099

4. If applied to an interface what would this ACL do?

Router(config)#access-list 25 deny 172.32.10.0 0.0.0.255
Router(config)#access-list 25 permit any

A) Deny traffic from the 172.32.10.0 network
B) Deny SMTP traffic from the 172.32.10.0 network
C) Deny traffic from the host 172.32.10.0
D) Deny SMTP traffic from the host 172.32.10.0
E) Allow all traffic

5.  Your network features a combination of Cisco, 3COM and Netgear switches. You have been tasked to set up VLANS on your switched network.

What trunking method should you use?

A) Inter-Switch Link
B) IEEE 802.1Q
C) You can't create VLANs by combining switches from different vend

6. When you connect to a remote router "out-of-band", via what port would you connect with?

A) Console port
B) Auxiliary port
C) Ethernet port
D) Serial port

Free Cisco labs for CCNA, CCNP and CCIE students!
Presented by René Molenaar - CCIE #41726

1. Answer A 

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

2. Answer E

Distribution layer (Workgroup layer): Ensures packets are properly routed between subnets and VLANs using LAN-based routers and Layer 3 switches. In the Distribution layer are:

• Firewalls, security, network policies, and network address translation (NAT) are configured.
• Routing between workgroups and VLANs is accomplished.
• Access lists, packet filtering, and queuing are implemented.

3. Answer A

Router#configure terminal
Router(config)#access-list ?
 <1-99>  IP standard access list
 <100-199> IP extended access list
 <1100-1199> Extended 48-bit MAC address access list
 <1300-1999> IP standard access list (expanded range)
 <200-299> Protocol type-code access list
 <2000-2699> IP extended access list (expanded range)
 <700-799> 48-bit MAC address access list
 rate-limit Simple rate-limit specific access list
4. Answer A

This standard ACL denys traffic from the 172.32.10.0 network and allows everything else.

5. Answer B 

ISL is a Cisco proprietary frame tagging method and therefore only works with Cisco switches.
IEEE 802.1Q is the networking standard that supports virtual LANs (VLANs) on an Ethernet network.

6. Answer B

When a router is out-of-band (out of the network) you would connect remotely via a modem attached to the auxiliary port.

Check back regularly, more questions every week 

(if time permits).

   “I seldom end up where I wanted to go, but almost always end up where I need to be.”

― Douglas Adams

Networking Questions 2016 - Part2

Another half a dozen random networking posers to get you thinking, have fun :-)


1. Lets start simple, What is port 23 used for?

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

2. 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

3. In a local broadcast all bits set to 1 are received by all hosts on local and remote broadcast domains?

A) True
B) False

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

A) True
B) False

5. 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

6. What do asymmetric switches require?

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






1.  Answer C

The Telnet is a TCP/IP protocol which defines a text based communications session between a client and a host using TCP port number 23.

2. 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.

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

3. Answer B

Routers don't forward broadcasts so local broadcasts will stay on the broadcast domain from which they originated.

 4. 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.

 5.  Answer A

STP switch port states:

Blocking
Listening
Learning
Forwarding
Disabled

A switch does not enter any of these port states immediately except the blocking state. When the Spanning Tree Protocol (STP) is enabled, every switch in the network starts in the blocking state and later changes to the listening and learning states.

6. Answer A

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

Progressively harder ?? stay tuned for more  

- thank you.

“A good teacher can inspire hope, ignite the imagination, and instill a love of learning.”

― Brad Henry

Networking Questions for 2016 - Part 1

A new set of half dozen networking questions to get you thinking.  


I'm going to expand into SDN, Security and NVF questions over the next few months to keep things current :-) Enjoy.

1. 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

2. What is the dotted decimal format of the loop back address?

A) 192.168.0.0
B) 127.0.0.1
C) 192.0.0.1
D) 227.0.0.1

3. What is the reserved address space for a Class C network?

A) 10.0.0.0 - 10.255.255.255
B) 20.0.0.0 - 20.255.255.255
C) 172.16.0.0 - 172.31.255.255
D) 192.168.0.0 - 192.168.255.255
E) 208.168.0.0 - 208.168.255.255 

4.  Where is the start-up configuration file held in a router?

A) NVRAM
B) RAM
C) Routing table
D) ROM

 5. 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

 6. What are the three layers of the Cisco hierarchical model?

A) Core layer, Network layer, Access layer
B) Core layer, Distribution layer, Access layer
C) Physical layer, Network layer, Transport layer
D) Media Layer, Transport layer, Application layer
 

Free Cisco labs for CCNA, CCNP and CCIE students!
Presented by René Molenaar - CCIE #41726

1. Answer E 

Trick question to start the series :-). IP provides no form of error correction/acknowledgements.

2.  Answer B 

127.0.0.1 is a special reserved IP address which is used as a host's loopback address. Messages sent to loopback address do not get placed on the LAN, instead they are re-routed by the host's own network adapter back to the receiving end of the TCP/IP stack.

3. Answer D 

http://en.wikipedia.org/wiki/Private_network#Private_IPv4_address_spaces

 
 4. Answer A

The IOS software in Cisco devices looks for a valid configuration file stored in NVRAM. which is called as startup-config. If a startup-config file is not in NVRAM, the router will start the setup-mode configuration upon boot up.

5.  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.

 6. Answer B 

Core layer: Considered the backbone of the network (high-end switches, high-speed cables). Concerned only with speed and reliable delivery of data. No packet filtering happens here.

Distribution layer (Workgroup layer): Ensures packets are properly routed between subnets and VLANs using LAN-based routers and Layer 3 switches.

Access layer (Desktop layer): Deals with connecting workstations to the network with switches and hubs.

How did you go?  Stay tuned for more in the coming weeks and months  :-)

 

 “Follow effective action with quiet reflection. From the quiet reflection will come even more effective action.”
― Peter Drucker

1Tbps: researchers break broadband speed record

Download entire Games of Thrones season in one second.

Researchers from the University College London (UCL) have
discovered the fastest ever data rate in digital information,
suggesting one day a movie could be downloaded within one second.





The researchers from UCL’s Optical Networks Group had achieved a rate
of 1.125 Tb/s as part of research on the capacity limits of optical
transmission systems. The research was designed to address the growing
demand for fast data rates.

Read more: http://www.crn.com.au/News/414953,researchers-break-broadband-speed-record.aspx#ixzz40JrzDWVY