CCNA1 Chapter 9

1
In the graphic, Host A has reached 50% completion in sending a 1 KB Ethernet frame to Host D when Host B wishes to transmit its own frame to Host C. What must Host B do?

Host B can transmit immediately since it is connected on its own cable segment.
Host B must wait to receive a CSMA transmission from the hub, to signal its turn.
Host B must send a request signal to Host A by transmitting an interframe gap.
**Host B must wait until it is certain that Host A has completed sending its frame.



2
Ethernet operates at which layers of the OSI model? (Choose two.)

Network layer
Transport layer
**Physical layer
Application layer
Session layer
**Data-link layer



3
Which of the following describe interframe spacing? (Choose two.)

**the minimum interval, measured in bit-times, that any station must wait before sending another frame
the maximum interval, measured in bit-times, that any station must wait before sending another frame
the 96-bit payload padding inserted into a frame to achieve a legal frame size
the 96-bit frame padding transmitted between frames to achieve proper synchronization
**the time allowed for slow stations to process a frame and prepare for the next frame
the maximum interval within which a station must send another frame to avoid being considered unreachable



4
What three primary functions does data link layer encapsulation provide? (Choose three.)

**addressing
**error detection
**frame delimiting
port identification
path determination
IP address resolution



5
When a collision occurs in a network using CSMA/CD, how do hosts with data to transmit respond after the backoff period has expired?

**The hosts return to a listen-before-transmit mode. <--- The hosts creating the collision have priority to send data. The hosts creating the collision retransmit the last 16 frames. The hosts extend their delay period to allow for rapid transmission.

6
What are three functions of the upper data link sublayer in the OSI model? (Choose three.) recognizes streams of bits
**identifies the network layer protocol
**makes the connection with the upper layers identifies the source and destination applications
**insulates network layer protocols from changes in physical equipment determines the source of a transmission when multiple devices are transmitting

7
What does the IEEE 802.2 standard represent in Ethernet technologies? MAC sublayer Physical layer **Logical Link Control sublayer Network layer

8
Why do hosts on an Ethernet segment that experience a collision use a random delay before attempting to transmit a frame?
A random delay is used to ensure a collision-free link.
A random delay value for each device is assigned by the manufacturer.
A standard delay value could not be agreed upon among networking device vendors.
**A random delay helps prevent the stations from experiencing another collision during the transmission.


9
Refer to the exhibit. Which option correctly matches the frame field type with the contents that frame field includes? header field - preamble and stop frame
**data field - network layer packet data field - physical addressing trailer field - FCS and SoF

10
Host A has an IP address of 172.16.225.93 and a mask of 255.255.248.0. Host A needs to communicate with a new host whose IP is 172.16.231.78. Host A performs the ANDing operation on the destination address. What two things will occur? (Choose two.)
Host A will change the destination IP to the IP of the nearest router and forward the packet.
Host A will broadcast an ARP request for the MAC of its default gateway. A result of 172.16.225.0 will be obtained.
**Host A will broadcast an ARP request for the MAC of the destination host. A result of 172.16.224.0 will be obtained.
**A result of 172.16.225.255 will be obtained.

11
Which of the following is a drawback of the CSMA/CD access method?
**Collisions can decrease network performance. It is more complex than non-deterministic protocols. Deterministic media access protocols slow network performance. CSMA/CD LAN technologies are only available at slower speeds than other LAN technologies.

12
Ethernet operates at which layer of the TCP/IP network model?
application physical transport internet data link
**network access

13
What is the primary purpose of ARP? translate URLs to IP addresses
**resolve IPv4 addresses to MAC addresses provide dynamic IP configuration to network devices convert internal private addresses to external public addresses

14
Refer to the exhibit. The switch and workstation are administratively configured for full-duplex operation. Which statement accurately reflects the operation of this link?
**No collisions will occur on this link. Only one of the devices can transmit at a time. The switch will have priority for transmitting data. The devices will default back to half duplex if excessive collisions occur.

15
Refer to the exhibit. Host_A is attempting to contact Server_B. Which statements correctly describe the addressing Host_A will generate in the process? (Choose two.)
A packet with the destination IP of Router_B.
A frame with the destination MAC address of Switch_A.
A packet with the destination IP of Router_A.
**A frame with the destination MAC address of Router_A.
**A packet with the destination IP of Server_B.
A frame with the destination MAC address of Server_B.

16
Which statements correctly describe MAC addresses? (Choose three.)
dynamically assigned
**copied into RAM during system startup layer 3 address
**contains a 3 byte OUI
**6 bytes long 32 bits long

17
Which two features make switches preferable to hubs in Ethernet-based networks? (Choose two.) reduction in cross-talk
**minimizing of collisions support for UTP cabling division into broadcast domains
**increase in the throughput of communications

18
What are the two most commonly used media types in Ethernet networks today? (Choose two.) coaxial thicknet
**copper UTP coaxial thinnet
**optical fiber shielded twisted pair

19
Convert the binary number 10111010 into its hexadecimal equivalent. Select the correct answer from the list below. 85 90
**BA A1 B3 1C

20
After an Ethernet collision, when the backoff algorithm is invoked, which device has priority to transmit data? the device involved in the collision with the lowest MAC address the device involved in the collision with the lowest IP address
**any device in the collision domain whose backoff timer expires first those that began transmitting at the same time

Attention: Next Terrorist Attack 13th January 2009

13th May : Jaipur Bomb Blasts

26th July : Ahmadabad Bomb Blasts

13th September : Delhi Bomb Blasts

26th November : Mumbai Terror Attack

13th January : Where????


It looks like the terrorists have planned to bleed us every alternate months either on the 13th or the 26th day.So now after the 26th November carnage in Mumbai. December may remain calm...But January??? Are the intelligence guys looking or not.

Mumbai Blasts: Unseen Photographs

alt=""id="BLOGGER_PHOTO_ID_5274453284993753682" />

CCNA 2 - Module 1 100%

CCNA 2 - Module 1

1. If a router cannot find a valid configuration file during the startup sequence, what will occur?
The router will prompt the user for a response to enter setup mode.

2. Refer to the exhibit. The network administrator has configured the router with the interface IP addresses shown for the directly connected networks. Pings from the router to hosts on the connected networks or pings between router interfaces are not working. What is the most likely problem?
The interfaces must be enabled with the no shutdown command.

3. Refer to the exhibit. What can be concluded from the routing table output in the exhibit? (Choose two.)
The FastEthernet0/0 and Serial0/0/0 interfaces of this router were configured with an IP address and the no shutdown command.
An IP packet received by this router with a destination address of 198.18.9.1 will be forwarded out of the Serial0/0/0 interface.

4. Refer to the exhibit. The frame shown in the exhibit was received by the router. The router interfaces are operational. How will the router process this frame? (Choose two.)
The router will change the frame type to one supported by the WAN link before forwarding the frame.
The frame was received on the Fa0/0 interface of the router and will be switched to the S0/0/0 interface.

5. Passwords can be used to restrict access to all or parts of the Cisco IOS. Select the modes and interfaces that can be protected with passwords. (Choose three.)
VTY interface
console interface
privileged EXEC mode

6. Which two statements correctly describe the components of a router? (Choose two.)
ROM contains diagnostics executed on hardware modules.
Flash memory does not lose its contents during a reboot.

7. Refer to the exhibit. After host 2 is connected to the switch on the LAN, host 2 is unable to communicate with host 1. What is the cause of this problem?
The subnet mask of host 2 is incorrect.
Host 1 and host 2 are on different networks.

8. Which are functions of a router? (Choose three.)
packet switching
segmentation of broadcast domains
selection of best path based on logical addressing

9. Refer to the exhibit. All routers have a route in its routing table to each network that is shown in the exhibit. Default routes have not been issued on these routers. What can be concluded about how packets are forwarded in this network? (Choose two.)
If RouterA receives a packet that is destined for 192.168.3.146, it will be forwarded out interface S0/0/1.
If RouterB receives a packet that is destined for 10.5.27.15, it will be forwarded out interface S0/0/1.

10. The serial connection shown in the graphic needs to be configured. Which configuration commands must be made on the Sydney router to establish connectivity with the Melbourne site? (Choose three.)
Sydney(config-if)# ip address 201.100.53.2 255.255.255.0
Sydney(config-if)# no shutdown
Sydney(config-if)# clock rate 56000

11. Refer to the exhibit. What can be concluded from the output of the running-configuration of a router?
The commands that are displayed determine the current operation of the router.

12. Refer to the exhibit. Host A pings host B. When R4 accepts the ping into the Ethernet interface, what two pieces of header information are included? (Choose two.)
destination IP address: 192.168.10.134
destination MAC address: 9999.DADC.1234

13. What is the outcome of entering these commands?
R1(config)# line vty 0 4
R1(config-line)# password check123
R1(config-line)# login
sets the password to be used for connecting to this router via Telnet

14. Which of the following is the correct flow of routines for a router startup?
load bootstrap, load IOS, apply configuration

15. What three processes does a router execute when it receives a packet from one network that is destined for another network? (Choose three.)
decapsulates the Layer 3 packet by stripping off the Layer 2 frame header
uses the destination IP Address in the IP header to look up the next-hop address in the routing table
encapsulates the Layer 3 packet into the new Layer 2 frame and forwards it out the exit interface

16. The network administrator needs to connect two routers directly via their FastEthernet ports. What cable should the network administrator use?
cross-over

17. Which two statements describe characteristics of load balancing? (Choose two.)
Load balancing allows a router to forward packets over multiple paths to the same destination network.
Unequal cost load balancing is supported by EIGRP.

18. What information about the router and its startup process can be gathered from the output of the show version command? (Choose three.)
the last restart method
the configuration register settings
the location from where the IOS loaded

19. Which interfaces in the exhibit could be used for a leased line WAN connection? (Choose two.)
1
4

20. From what location can a router load the Cisco IOS during the boot process? (Choose two.)
TFTP server
Flash memory

21. A network administrator has just entered new configurations into Router1. Which command should be executed to save configuration changes to NVRAM?
Router1# copy running-config startup-config

22. What is the default sequence for loading the configuration file?
NVRAM, TFTP, CONSOLE

23. What header address information does a router change in the information it receives from an attached Ethernet interface before information is transmitted out another interface?
the Layer 2 source and destination address

10 things to like about google chrome

1. Open Source

Being open source helps open the doors to all sorts of goodies in the form of extensions, plugins, and addons. Firefox’s success today comes from the fact that any feature you can imagine has been implemented as an extension.

Chromium, Google Chrome’s open source project was opened shortly after the beta release. Here’s a couple of tidbits you might be interested in. Chromium uses Subversion as it’s version control system and it was written in C++ using Visual Studio 2005.

2. The Speed

Holy crap, Chrome is fast. The UI is responsive, pages load quickly, and the Javascript is blazing fast. CNET compiled a nice set of benchmarks comparing Chrome to the other major browsers and the end results speak for themselves.

Credit: Stephen Shankland/CNET News

Chrome won’t be holding the top spot for long if Tracemonkey lives up to its reputation. According to a press release from Mozilla, Firefox 3.1’s Javascript engine will be faster than Chrome’s V8.

3. Existing Rendering Engine - WebKit

It’s not that I like WebKit. It has quirks just like every other rendering engine. What I like is that Google decided to use an existing engine to power Chrome instead of rolling their own. Every site we build here at SOTC goes through the gambit of browsers - Firefox, IE6, IE7, Safari, and Opera. It’s challenging enough making a site work across the board and the last thing web developers need is another browser to add to the list. In most cases, a site made to work in Safari will work in Chrome without any problems.

4. Tab Processes

Every tab you create in Chrome spawns a new process (unless two tabs are visiting sites with the same top-level domain). This prevents a single tab from crashing the browser or making it unresponsive by consuming too many resources. Javascript being executed in one tab does not affect any other tab. Flash, however, still does. In fact a Flash animation can render the entire browser unusable if it’s using the entire processor. It’s something all browsers suffer from and hopefully Adobe will address it in the future.

5. The Task Manager

Every tab and every plugin are displayed in Chrome’s task manager. This helpful little utility makes finding the site or plugin that is hosing the processor much easier than it used to be.

6. Text Search Location Highlighting

Ok, so I don’t know the technical term for this feature, but when you search for text (control-F), Chrome will highlight on the scrollbar places in the document where that term is found. It’s a simple feature, but one that is extremely useful.

7. The Omnibar

Chrome’s Omnibar is pretty close to Firefox’s Awesome Bar, with a few exceptions. First of all, the Omnibar will suggest other sites for you that you haven’t even visited yet. It’s also a replacement for the search box. Just type something in the box and if it’s not a website, it will search for the term using the search engine of your choice (defaults to Google, of course).

8. The Stability

I’ve been using Chrome on two different computers with two different operating systems exclusively for two straight days and I have yet to make it crash. Firefox 3 didn’t fair so well when it first came out. If the announcement comic is correct, they perform some serious testing on each build of the browser.

9. Tab Dragging

In Chrome, you can grab a tab, dislodge it from it’s current window and either drop it on the desktop to create a new window, or drop it inside another Chrome window as a new tab. I don’t know if I’ll ever actually use the feature myself, but it’s really fun to play with.

10. Incognito Mode

In Chrome, you can create a new window, called an Incognito window, that doesn’t save any information about where you’ve been or what you’ve done. According to Google, you might want something like this if you’re buying a gift for someone that shares your computer, and you don’t want them to know what you’ve been looking at. Various bloggers and reviewers, however, have a different use in mind.

Encryption

Privacy has been the prime requirement for the modern day man. We ofter hear - Privacy is dead. Is it? To some extent though it is, but the reason is not those that made it die, but those that left their privacy wide open to all. Privacy is there, as long as you let it be.

Today's cyber world is filled with prying eyes, with people trying to know about you. The information they will try to gather ranges from your email id, passwords, your emails etc. This post will try and concentrate on the email privacy stuff.

Email privacy has been a concern, ever since email became reality. Emails started back in the eighties. The thing that concerns us is that whenever we send mail, it passes through a number of routers, that come in between the smtp server and the pop server. Many routers will make a local copy of these data, and store them for further retrieval. In many places, in cyber cafes, keyloggers would be common, that not only log your passwords, but whatever you type in the keyboard. In short, it will monitor your site visits, your passwords, your emails and what not. Most of this is done due to Government implementations, others for private misuse purposes. But we can actually prevent all this, if we take certain measures.

Email encryption has been around for a long time now, but still there are many that would prefer to send unencrypted messages, unknowing that they can be sniffed in between, used for various other purposes like privacy theft, identity theft etc. But with 4096 bits encryption around, if the misuser does not possess a set of a few supercomputers, there is no way to break the encryption.

One can use the various applications for the encryption and then use a mailer to send the mails through smtp servers. In present date, most mail servers are free and most of them won't allow pop access to mails, unless you upgrade to premium accounts, for which you'd have to pay. Gmail is the only provider, that I know, provides POP as well as IMAP access for free. As for the encryption application, one can use GNU's Privacy Guard the GNUpg and for the mailer application, one can use the MS Outlook, if one uses windows, or the Mozilla Thunderbird or Sea Monkey. I'd suggest Thunderbird, for it's free and it has less bugs as compared to the "MICROSOFT" Outlook. If using Thunderbird, one can use the Enigma Add-On, available on mozilla's site (www.mozilla.org).

All th algorithms will have two keys. One will be the Private key, and the other will be the Public key. While they are generated, the application may ask you to move your mouse or type random things on the keyboard or surf the internet or do disk intensive tasks. This is, so that it can generate random key, that is hard to guess. The public key is used to encrypt the message and the private key is used to decrypt it. After the generation, you will need to distribute the public key, or store it in some website or something. Keep the Private key secure with you.

Routers

Routers are the most insecure computers that exist on the Internet. There are so many routers in this world, that you can 0wn as many as you want. The most predominant reason for this lack of security of routers, is that most are not configured at all. They are left with their default passwords (I know this from personal experience). Because of this, routers are very easy to exploit. All you need to do is find out which Operating System it is using, and then just grep out the default passwords list for that. How to find the OS? Go read about nmap, stupid boy!

As routers have to work all the times, they are always on, but again they may log your data, and you may not be able to delete it. But since routers get so huge an amount of traffic everyday, that your chances to escape, literally increases very much. When you decide to exploit a router, use a wingate first, and then connect to it. Why take chances?

How to find them:

Finding routers is easy. I'll tell the most easy way. One that I had incorporated to find routers. Go to google, and search anything, then traceroute all the sites that show up. All the computers that come between yours and theirs, are routers. Then you have to scan each one for the operating system. It's that easy.