Posts from ‘CCENT’

Dec
01

Catalyst switch port security is so often recommended. This is because of a couple of important points:

  • There are many attacks that are simple to carry out at Layer 2
  • There tends to be a gross lack of security at Layer 2
  • Port Security can guard against so many different types of attacks such as MAC flooding, MAC spoofing, and rouge DHCP and APs, just to name a few

I find when it comes to port security, however, many students cannot seem to remember two main points:

  1. What in the world is Sticky Learning and how does it work?
  2. What is the difference between the different violation modes and how can I remember them?

Sticky Learning

Sticky learning is a convenient way to set static MAC address mappings for MAC addresses that you allow on your network. What you do is confirm that the correct devices are connected. You then turn on sticky learning and the port security feature itself, for example:

switchport port-security maximum 2
switchport port-security mac-address sticky
switchport port-security

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Oct
17

For Part 2 of this series – click here.

WARNING: You must master subnetting using our course or some other trusted materials before you start using these shortcut approaches. It is a common issue for Cisco candidates to move directly to subnetting shortcuts for the exams without fully understanding exactly how subnetting functions.

ICND1 (CCENT)

Question 3: Your co-worker has decided upon use of the 172.16.0.0 address space for a section of your network. This section requires 15 subnets. What subnet mask will you recommend?

Step 1: I reference the Powers of Two chart I created on my scratch paper when I encountered the first question. The forumla for the number of subnets you can create based on subnet bits is 2^s. From the chart I see if we “borrow” 4 bits we can create 16 subnets.

2^7=128  |  2^6=64  |  2^5=32  |  2^4=16  |  2^3=8  |  2^2-=4 | 2  ^1=2  |  2^0=1

Step 2: Borrowing 4 bits beyond the Class B boundary results in 255.255.128+64+32+16 = 240. Our mask is 255.255.240.0.

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Oct
14

Click here for Part 1 of this series.

WARNING: You must master subnetting using our course or some other trusted materials before you start using these shortcut approaches. It is a common issue for Cisco candidates to move directly to subnetting shortcuts for the exams without fully understanding exactly how subnetting functions.

ICND1 (CCENT)

Question 2: You have run the ipconfig command and discovered your IP address and mask are 192.168.20.102 and 255.255.255.224. How many hosts are permitted on your subnet?

Step 1: I reference the Powers of Two chart I created on my scratch paper when I encountered the first question. Adding 128 + 64 + 32 = 224. There are 3 bits used for subnetting and that leaves 5 bits for hosts.

2^7=128  |  2^6=64  |  2^5=32  |  2^4=16  |  2^3=8  |  2^2-=4 | 2  ^1=2  |  2^0=1

Step 2: The equation for the number of hosts per subnet is 2^h – 2 where h is the number of host bits. From the chart I see that 2^5  = 32. 32-2 = 30 hosts per subnet! Too easy!

As always, let us know in the comments if you have a quicker approach.

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Oct
02

Thanks to Randy of our CCNA program for this suggestion. Randy wanted some guidance on how to solve the subnetting questions in ICND1 and ICND2 very quickly. The ability to do this is often the difference between a passing score and a failed attempt.

WARNING: You must master subnetting using our course or some other trusted materials before you start using these shortcut approaches. It is a common issue for Cisco candidates to move directly to subnetting shortcuts for the exams without fully understanding exactly how subnetting functions.

For this series of posts, we will use simulated exam questions from ICND1 and ICND2. Well, with all that out of the way – let’s have some fun. You will find that once you “turn the corner” on subnetting, you will pray for many of these questions in the exam. It is an opportunity to solve questions quickly and be 100% convinced that your response is “spot on”.

ICND1 (CCENT)

Question 1: What is the last usable address in the subnet of a host with the address 192.168.1.134 and the subnet mask of 255.255.255.240?

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Sep
07

One of our CCNA students requested some command practice for ICND2 – here is one I put together for him. Please give me feedback in the comments if you find practice tools like this helpful.

ICND2 Command Recall Practice Tool 1

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Sep
01

Are you a CCNP or CCIE student looking to challenge your perfect knowledge of Catalyst switchport commands?

Take the latest SWITCH Command Recall exam by clicking the link below. Good luck – and let us know how you scored in the comments area of this post.

Remember to read, AND TYPE, very carefully! I failed my first attempt due to just plain sloppiness. :-(

SWITCH Command Recall Exam – L2/L3 Ports

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Aug
18

As you may have noticed, INE does a wide variety of training in the Cisco space.  :)     This blog post goes out to all those folks who have recently begun their Cisco training.

This month we delivered new live classes on CCNA and CCNP. We are excited for and encourage our students at every level in their journey.   In that light, we have gathered a collection of Videos Answers, targeted at the CCNA level, with a few topics leaking into security and CCNP.   These videos were primarily created as quick (under 10 minutes each) Video Answers to questions that various learners have had.

Take a look at the list of topics, and if there are 1 or 2 you feel you would benefit from, feel free to enjoy them.

Here are a few of the topics (in no particular order):

  • How the network statement really works in IOS
  • Setting up SSH
  • Initial commands for sanity sake
  • NAT with overload
  • Router on a stick
  • VRFs Continue Reading

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Jul
23

Are you wondering what the month of August 2010 will bring for INE fans?

Try all new, online bootcamps in the following disciplines:

  • MPLS
  • BGP
  • CCNA
  • CCNP
  • CCDA

Watch the blog and your email for all of the exciting new details.

Join the INE Experts Online in August

Join the INE Experts Online in August

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Apr
25

Here ye, here ye, VTP experts. (We are not referring to the Vandenberg Test Program, although they are very likely experts in their field as well.  :) )

Can you predict the results of a 3 switch VTP client/server scenario?

SW1-3, are connected, as shown in the diagram.

VTP question for Blog

Here is the initial output of show VTP status, and show VLAN brief on each. Note that SW1 and SW3 are servers, while SW2 is a client.   We will be adding a failure to the network in just a moment. Continue Reading

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Mar
23

This blog post is taken from the INE Resources area Understanding Frame-Relay Traffic Shaping presentation by Brian Dennis.

Overview

Frame-Relay traffic shaping is designed to control the amount of traffic the router sends out of an interface or out of a particular DLCI. Common reasons for Frame-Relay traffic shaping are:

  • It allows the router to conform to the rate subscribed with the service provider
  • It allows for the throttling of a higher speed site (768K) so that it does not overrun a lower speed site (64K)

Traffic shaping is designed to delay excess traffic, whereas policing is designed to drop excess traffic.

Terminology

  • Available Rate (AR) – the actual physical speed of the interface; on a DCE serial interface this is determined by the configured clock rate. On a DTE serial interface, it is determined by the received clock rate. A router will always (by default) try to send out at the AR regardless of the interface bandwidth. AR is also commonly referred to as port speed, line rate, or access rate.

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