Is the blog stats still work?

Posted on April 10, 2016. Filed under: CCNA |

  • 552,216 hits at April 10th., 2016.

yes, it is still increasing.

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Posted on April 3, 2016. Filed under: CCNA | xxxxx ICND1 And ICND2 Break Down xxxxx Switch foundation xxxxx why the minimum ethernet packet size is 64 bytes xxxxx Answer for DnD2 xxxxx WAN trouble-shooting commands xxxxx public switched telephone network (PSTN) xxxxx What is WAN xxxxx Switch/Router Interfaces and Physical Ports xxxxx Basic Router Management Commands xxxxx WLAN Security xxxxx enable password vs enable secret xxxxx Cisco IOS software overview xxxxx Host-to-Host communication xxxxx Host-to-Host communication through a Switch xxxxx Ethernet LAN Segments xxxxx Ethernet Frame xxxxx What is a LAN ? xxxxx TCP/IP Applications xxxxx UDP Header xxxxx TCP Header xxxxx IP and ICMP protocols xxxxx CIDR network address xxxxx Private IP address ranges xxxxx IP addressing xxxxx The need for network security xxxxx Classes of Attack xxxxx CCENT Final Practice Exam 4 — 22 Question Set xxxxx CCENT Final Exam Practice 1 — 50 Question Set xxxxx CCENT Final Exam Practice 2 — 50 Question Set xxxxx CCNA Practice Exam 1– 50 Question Set xxxxx Configuring Cisco ASA/PIX 7.x for SSH xxxxx Routing Process Continued — Behind the PING xxxxx 5-4-3 rule xxxxx Module 11 Exam xxxxx Exam 14 — 15 Question Set xxxxx Module 10 Exam xxxxx Exam 12 — 20 Question Set xxxxx Module 9 Exam xxxxx Module 8 Exam xxxxx Module 7 Exam xxxxx Module 6 Exam xxxxx Module 5 Exam xxxxx CCENT Module 4 Exam xxxxx Module 3 Exam xxxxx Module 2 Exam xxxxx Modual 1 Exam xxxxx CCENT Final Practice Exam 3 — 51 Question Set xxxxx CCENT Final Exam 3 — 51 question set xxxxx Floating Static Route xxxxx CCNA And CCENT Practice Exam Questions — 10 Questions On The OSI And\nTCP/IP Models xxxxx Answers for Interconnecting Cisco Networking Devices (ICND) Practice\nQuestions-Module 6 xxxxx Answers for IInterconnecting Cisco Networking Devices (ICND) Practice\nQuestions – Module 5 xxxxx Answers for IInterconnecting Cisco Networking Devices (ICND) Practice\nQuestions – Module 5 xxxxx Answers for Interconnecting Cisco Networking Devices (ICND) Practice\nQuestions-Module 4 xxxxx Telnet and SSH Maintenance Commands xxxxx L1 and L2 Troubleshooting xxxxx Cisco Discovery Protocol (CDP) xxxxx Preventing Virus Attacks xxxxx Antena types xxxxx Spread spectrum xxxxx Physical Side of Cisco Switches xxxxx Physical Connections and Passwords xxxxx Basic Switch Security xxxxx Cisco's 3 Layered Model xxxxx Forwarding modes xxxxx The Data Transmission Process xxxxx The TCP/IP Model xxxxx Answers for Interconnecting Cisco Networking Devices (ICND) Practice\nQuestions -Module 3 xxxxx Crosstalk xxxxx Answers for Interconnecting Cisco Networking Devices (ICND) Practice\nQuestions – Module 2 xxxxx What is CCNA Voucher, CCNA Exam Voucher, CCNA Discount Voucher, or CCNA\nCertification Voucher xxxxx Decimal > Binary, Binary > Decimal xxxxx Convert Binary Numbers and IP Addresses xxxxx Subnetting Scenarios xxxxx Subnetting Basics xxxxx Static Routing Theory xxxxx Comparing RIP Versions 1 and 2 xxxxx Intro to PIX, ASA, IDS, and IPS xxxxx The Attacker’s Arsenal xxxxx Viruses, Worms, and Trojan Horses xxxxx Firewalls and Proxy Servers xxxxx Introduction to Frame Relay xxxxx “logging synch”, and “exec-timeout” xxxxx The Configuration Register xxxxx Introduction to ATM xxxxx HDLC and PPP xxxxx WAN interface of Cisco Router and WAN cabling xxxxx Modem and DSL variations xxxxx Physical Side of WANs xxxxx Managing Startup Files and IOS Images xxxxx Setup Mode xxxxx Cisco Router Memory xxxxx Startup Sequence xxxxx An overview of Wireless Security xxxxx SSIDs and MAC Address Authentication xxxxx CSMA/CA vs CSMA/CD xxxxx IEEE 802.11 Standards Comparison xxxxx Intro to Wireless LAN xxxxx Setting Switch/Router Banner xxxxx Intro to Cisco Security Device Manager (SDM) xxxxx Intro to the Routing Process xxxxx Keystroke Shortcuts and Manipulating History xxxxx Basic Management Commands for The Switch xxxxx Switch Virtual LANs xxxxx Switch Port Security Defaults, Options and Configurations xxxxx Introduction to STP xxxxx Repeaters, Hubs, Bridges, Switches and Routers xxxxx Bridges and Switches — Flood, Filter or Forward? xxxxx Ethernet Addressing xxxxx IP Addressing xxxxx ICND1 break down – Pins And Transmissions xxxxx ICND1 break down – Operation of CSMA/CD xxxxx Ethernet Standards xxxxx Ethernet Standards xxxxx ARP, RARP and DHCP xxxxx ICND1 break down — Telnet and SSH xxxxx ICND1 break down — DNS Basic xxxxx Debugging Internet Routing Problems with Traceroute xxxxx Data Transmission xxxxx Ports, Sockets, Port Numbers and Multiplexing xxxxx NEED – Senior/Lead Java, Oracle, Web Developer & Analyst xxxxx Software Applications Developer Position Available in Florham Park, NJ xxxxx ICND1 break down — Broadcasts, Unicasts, And Multicasts xxxxx ICND1 break down — Pings and extended pings xxxxx ICND1 break down — An OSI Model Review xxxxx ICND1 break down — Switch/Router Passwords And Encryption xxxxx ICND1 break down — Router Configuration Modes xxxxx ICND1 break down — Configuration Modes xxxxx ICND1 break down — What is A Network xxxxx Iphone Developer xxxxx CCNA Lab Video Tutorial 6 – Router as DHCP Server xxxxx CCNA Lab Video Tutorial 5 – Internet Connections with NAT and PAT xxxxx CCNA Lab Video Tutorial 4 – Ref3 – OSPF Routing Command xxxxx CCNA Lab Video Tutorial 4 – ref2 – EIGRP Routing Command xxxxx CCNA Lab Video Tutorial 4 – ref1 – STATIC Routing Command xxxxx CCNA Lab Video Tutorial 4 – Configuring STATIC ROUTING, RIP, EIGRP and\nOSPF xxxxx 640-802 CCNA® Exam Topics (Blueprint) xxxxx 640-816 ICND2 Exam Topic (Blueprint) xxxxx Looking for Network Serives professionals xxxxx Cisco Router Basic Commands video tutoial – Configure Routing Protocal xxxxx Cisco Router Basic Commands video tutoial – Configure Serial interface xxxxx Cisco Router Basic Commands video tutoial – Configure FastEthernet\ninterface xxxxx CCNA Lab Video Tutorial 3 – Cisco Router Basic Commands xxxxx Package Tracer Video Tutorial – Trouble Shooting xxxxx Packet Tracer video tutorial – Connect two Switches with a Router xxxxx Packet Tracer video tutorial – Getting started xxxxx Packet Tracer video tutorial -DHCP setup xxxxx CCNA Lab Video Tutorial 2 – Packet Tracer Interface overview xxxxx CCNA Lab Video Tutorial 1 – CCNA virtue lab with Packet Tracer xxxxx Cisco ISO simulator for Linux xxxxx Linux router vs Cisco router xxxxx ICND1 break down — TCP and UDP xxxxx ICND1 break down — Network Topologies xxxxx ICND1 break down — Ethernet Connectors and Cable Types xxxxx ICND1 break down — Cable Category (cat 1, cat2, cat3, cat4, cat5, cat6) xxxxx ICND1 break down — IP Address Classes xxxxx ICND Practice Questions- Module 1 xxxxx Contact Me xxxxx Contact Me xxxxx Thank you for the message xxxxx Mobile Application Web Developer xxxxx ICND1 break down — NAT & PAT xxxxx NAT & PAT xxxxx CCNA Lab: How to setup VPN Server at home xxxxx ICND1 and ICND2 break down xxxxx Should You Take The Single or the Two Exam Approach To CCNA? xxxxx 640-822 ICND1 Exam Topics (Blueprint) xxxxx Java developers needed in Charlotte, NC….please refer ($) if you can\n- thanks!! (expired…) xxxxx Top IT certification websites xxxxx The resources for IT test xxxxx What Test to take? — Make Plan xxxxx friend blogs xxxxx Hello world!

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Protected: Q & A 1

Posted on November 2, 2012. Filed under: Others |

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SANS Developer 541 Secure Coding In Java/JEE: Developing Defensible Applications

Posted on November 2, 2012. Filed under: CCNA |

You will have 180 minutes to complete 75 questions.

This exam features scoring that enables you to monitor your progress in near real time. After you have answered your fifteenth question, you will see the checkpoint score for the first 15 answers. This allows you to roughly monitor how you are progressing relative to the passing score of the exam. The checkpoint score will be updated at fifteen question intervals. For example: in this 75 question exam, an updated checkpoint score will be displayed after answering 15, 30, 45, 60, and 75 questions respectively.

If you experience any technical problems during your exam that involve a loss of exam time, please notify your proctor immediately and mention that GIAC exams are Running Clock Exams. The exam clock does not stop when there is a technical issue, and lost time must be added back by GIAC Exam Support.

Answer each question to the best of your ability on the exam. We encourage you to provide feedback to improve the certification process. You will have the opportunity to mark 10 questions for review by the GIAC exam team. To mark a question for review, click the “Flag Previous” button at the top-right of the exam console AFTER you have answered the question. You will NOT be able to go back and answer these questions again.

Please flag any questions that you feel contain:

  • Typographical errors (spacing, formatting, etc.)
  • Spelling and grammatical errors
  • Technical inaccuracies
  • More than one right answer

At the conclusion of your exam, you will have a chance to comment on the questions you marked individually. If you have specific comments or questions please provide as much information as possible.

GIAC does NOT award credit on commented exam questions, however, your comments will still be used to improve the exam.

You have the option to skip 5 questions during your exam. These questions will not be displayed again until you are close to the end of the exam. You also have the option to take 1, 15-minute break during the course of your exam. Please note, however, that any questions you skip during the exam, must be answered by clicking the “Answer Skipped” button BEFORE you take a break.

During your practice exam, you will be shown explanations by default on questions you answer incorrectly. You may optionally choose to see explanations for ALL questions you encounter on your exam, as well as disable showing explanations all-together by selecting the appropriate option at the top-right corner of the exam console.

For security reasons you will NOT be able to view the answer options for marked questions. Take any notes you require during your exam, because you will NOT be able to go back. You will have the opportunity to complete an exam evaluation at the conclusion of the exam. We welcome your comments.

For further information regarding the feedback procedure, please see the Exam Feedback Procedure page.

The questions used on this exam are considered confidential. You are NOT permitted to discuss or distribute them. Unauthorized disclosure or discussion of test questions is an ethics violation under GIAC and may result in financial liability.

DO NOT use your browser’s back button or refresh button once you start your exam. This can cause unpredictable results.

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Your time starts once you press the ‘Start Exam’ button below.

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Remove exchanged link

Posted on July 22, 2011. Filed under: Others |

Tech blog domain name is no longer exist, removes it from Blog roll, thanks for exchanging link with me, kuliahku!

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Switch foundation

Posted on July 22, 2011. Filed under: ICND2 break down |

In this class, we will review the basic concepts learned in ICND1 – Lession 3 Switching.

  • Switch is a Layer 2 network device, it forward frames based on the destination MAC address.
  • MAC Address table: When switch receives frame from new source MAC address, it creates an entry in its MAC address table or content addressable memory (CAM) table. This entry is the receiving port and the source MAC address of the frame.
  • Flooding: when switch forward a frame, it will check its CAM table for the destination MAC address. If there is an entry for the destination MAC, it forwards to that port, otherwise it forwards to all ports, except the port the frame was originally received from, this is called flooding.
  • Switching Loops and Broadcast storm: in muti-linked networks, redundent links can form a loop, called switching loop. A frame with new source MAC address can tranverse a switching loop and gets repeatly broadcasted, which is called broadcast storm. To prevent broadcast storm, STP protocal is used.

There are 3 main switch transmission methods:

  • Store-and-Forward: stores a receiving frame in memory and runs CRC check, and only forward frame if CRC passes.
  • Cut-Trough: only looks at enough of the frame for destination and forward.
  • Fragment-Free: checks the first 64 tytes of a frame before forwarding, because most of the collision happened in the first 64 bypes.
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why the minimum ethernet packet size is 64 bytes

Posted on February 26, 2010. Filed under: CCNA |

The following is the answer for ATul Singh about Ethernet Frame:

The smallest packet size is 64 bytes.
14 bytes (MAC Header) + 46 bytes (Data) + 4 bytes (CRC) = 64 bytes

The smallest packet size is defined in RFC document (RFC894), I don’t know why IEEE like the number 64. As far as I concern, physics sets a low bound for the packet size. let’s review what we have learned in operation of CSMA/CD :

“If two NICs simultaneously try transmit, then both could see no carrier signal in the medium, thus decide to transmit and a collision will occur.  Collision Detection (CD) resolved this problem. When there is data waiting to be sent, each transmitting NIC will observe if a collision occurs (excess current i.e. >24mA for coaxial Ethernet). If  collision is detected, it stops transmission and sends a 32-bit jam signal instead. The receiving NIC will discard the corrupted frame due to the jam signal.”

Remember, a packet is a electromagnetic wave. For small sized packet, the wave is narrower, for large sized packet, the wave is wider.

In the following pictures, the squres represent ethernet cable, the curves represent ethernet packets (or electromagnetic waves). Suppose the node at point A and node at point C send two packets simultaneously, the node at point B will receive a corrupted data.

picture 3 is the normal situation where the packet size is large or the eletromagnetic wave is wider. When the eletromagnetic waves overlap (or packets collide) at node B, they also overlap at Node A and Node C. Therefore, both node A and node C sensed excess current and terminated the packet transmission and sent jam signals instead. Node B receives jam, discarded the corrupted packet.

In picture 1 and 2, since the packet size is too small, problem arises.

As picture 1 shows, at time 0, node A send a packet towards node B and C, while node C sends a packet towards node B and A at the same time.

As picture 2 shows, at time t, the eletromagnetic waves overlap (or packets collide) at node B, but they are not overlap at Node A or Node C. As a result, neither node A nor node C sensed excessive current, so no jam signals sent. In another words, a collision is not discovered and node B happily accepted the corrupted data!

IEEE might do their research and calculation, and find out that 32 bit packets may be too small for large LANs, 64 bit packet is large enough for even the largest LANs, so they picked the number 64. Just my guess.

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WAN trouble-shooting commands

Posted on November 12, 2009. Filed under: CCNA, ICND1 break down |

Let’s talk a little bit about IOS commands for WAN trouble-shooting.

To verify the physcial cable connection on the routers, “show controller serial 1”, where serial 1 is the serial port the cable attached to.

R1#show controller serial 1

For the sake of trouble-shooting, we may want to use command “show interface serial1” to gain more information about the interfaces. Sometimes we find that the physical interface is up and the line procol down, generally there could be two reasons

We forget to set the clock rate on DCE. The line protocal will be down after 30 seconds, because the DTE need to receive the clock rate to work correctly. To set the clock rate on the DCE, use command “clock rate 56000” to set the clock rate to, for instance, 56 kbps.

The encapsulation type mismatch on both ends of the connection.

For example, if we physically connected router R1 and R2, but set different encapsulation type on them.

R1#encapsulation ppp

R2#encapsulation hdlc

Then, we will see physical interface up and line prococal down by running command “show interface serial1” on both router R1 and R2. To resolve the problem, we issue command “encapsulation hdlc” on R1 or issue command “encapsulation ppp” on R2, so that the encapsulation type matches on both ends of the serial link.

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public switched telephone network (PSTN)

Posted on November 12, 2009. Filed under: CCNA, ICND1 break down |

The public switched telephone network (PSTN) is the network of the world’s public circuit-switched telephone networks, in much the same way that the Internet is the network of the world’s public IP-based packet-switched networks. Originally a network of fixed-line analog telephone systems, the PSTN is now almost entirely digital, and now includes mobile as well as fixed telephones. There are many advantages for PSTN as a communications link:

  • Other than a modem, no additional equipment is required.
  • The cost associated with the implementation of a PSTN connection link for a WAN is relatively low.
  • The maintenance of a public telephone network is very high quality with few instances in which lines are not available.
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What is WAN

Posted on November 12, 2009. Filed under: CCNA, ICND1 break down |


Wide Area Network (WAN) is a computer network that covers a broad geographical area. On the contrary, Local Area Networks (LAN) are usually limited to a small physical area, like a home, office, building  or campus.  The largest and most well-known example of a WAN is the Internet.

WANs are used to connect LANs and other types of networks together. Many WANs are built for one particular organization and are private. Others, built by Internet Service Providers (ISP), provide connections from an organizations’s LAN to the internet. In order to provide connections over large geographical arears, WANs often use public networks, such as the telephone system, leased lines (ISDN), satellite, microwave, or other connection method.

Typical WANs use serial connections of various types to access bandwidth over large geographic areas.

So, who is managing the WANs today? The following organizations defined and managed the WAN access standards:

  • International Organization for Standardization (ISO)
  • Telecommunications Industry Association (TIA)
  • Electronics Industry Alliance (EIA)

WAN access standards are primarily resides in OSI reference model Layer 1 and Layer 2. WAN access standards decribe physical layer and data link layer requirements such as physical addressing, flow control, and encapsulation. The following picture shows the popular WAN solutions today.


As shown above, at OSI model layer 1, WAN protocols describe how to provide electrical, mechanical, operational, and functional connections to the services of a communications service provider.

At OSI model layer 2,WAN protocols define encapsulation of data for transmission toward a remote location and the mechanisms for transferring the resulting frames. The WAN data link layer protocols include:

  • HDLC
  • PPP
  • Frame Relay (Link Access Procedure for Frame Relay [LAPF])
  • ATM

Serial connections support WAN services such as dedicated leased line, above which the PPP or Frame Relay runs.

Other WAN services, such as ISDN or dial-up modem, offer low cost dial-on-demand connection. An ISDN BRI is composed of two 64-kbps bearer channels (B channels) for data, and one 16-kbps data channel(D channel) for link-management purposes.

DSL and cable modem connections dominates today’s residential broadband service market. A typical residential DSL service can offer up to 1.5 Mbps connection speed over the existing telephone line. Cable services can offer higher speed connection over the existing coaxial cable TV line.

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