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Introducing Routers and Switches

March 5, 2013 at 10:03 pm

In this post for ICND1 students, Anthony Sequeira introduces routers and switches and demonstrates their capabilities, which are of course routing and switching!

What is 127.0.0.1 Really All About?!?!

March 3, 2013 at 7:27 pm

It is always so entertaining to see the exact questions that I had when I was starting my Cisco Certification pursuits. First off – congratulations in your choice to study this material – and thank you for reading my blog!!! please consider posting feedback and questions in the comments section. Every question and every comment is responded to promptly.

Now on to the question….

Why do we have the Loopback address and why is it 127.0.0.1??? Early on when the Department of Defense in the US was designing TCP/IP, they decided that they should reserve a portion of the space for testing. They rather randomly selected the 127 space for this purpose. In fact – it is the entire space 127 space that they reserved. Many do not realize this, since the most common implementation is to assign 127.0.0.1. So try pinging the address 127.1.2.3 on your PC and it might just respond if your vendor supports testing with other numbers in the reserved loopback space.

icones_00584

What is the fact that your machine responds to 127.0.0.1 really telling you??? This is telling you that TCP/IP is properly initialized on your device. You might not have external interfaces set up properly,but the TCP/IP stack is indeed there and it is functional once you do the remaining required configurations.

Notice the creators of TCP/IP had no idea there would be an IP address shortage when they selected this space! They sure wasted a lot of addresses for this testing purpose.

Remember also that you can create your own loopback interfaces on Cisco devices. For example, you can do this:

interface loopback 101
ip address 10.10.10.1 255.255.255.0

This creates a virtual interface on your device that you can use for a wide variety of purposes – like testing a feature!

When is the CCIE – X Changing?!?!

March 2, 2013 at 7:57 pm

Here is a question I still get very frequently – “Anthony – have you heard anything about the CCIE R&S changing soon???” In fact, you can insert any of the CCIE tracks where you see R&S in the question. 🙂

stress

This post is a reminder of the golden rule that Cisco follows with their CCIE Lab Exams…when they OFFICIALLY announce a change in the CCIE Lab Exam Blueprint for any track, there is a six month counter that starts upon the official announcement. That is right! What a great safeguard in your preparation. Now you know that even if they announce a change, you are guaranteed six months from that announcement before the change actually takes effect.

Notice how I highlighted the word officially. Many times, there will be speculative posts, and even preliminary posts by Cisco themselves. So how do you know what is the official announcement? It will be posted on the CCIE News section of Cisco.com.

For some students this would not be nearly enough time to be prepared if they just started their studies, but for others that are deep in their prep – this is an excellent safeguard.

Happy studies and I would love to see your comments or answer any of your questions here.

Who is Hacking Who?

February 20, 2013 at 3:47 am

China is upset with US claims that hacking attacks are being sponsored by the Chinese Government. Check out the full story here. Notice the very interesting statistics on hacking highlighted in this article!

Click Here for the Full Story!

CCENT Challenge 1 – Host to Host Communication

February 19, 2013 at 2:06 am

Examine the graphic below:

routers-and-switches

 

Snow_White sends a packet to Grimm. Grimm then responds with a packet to Snow_White. What is the source IP and source MAC address of this packet when it arrives at Dopey? Answer in the form of : IP address of Fa0/0 of Grumpy and MAC address of Fa0/3 of Happy.

Good luck – you will find the answer posted in the comments section of this blog.

Facebook Hit with “Watering Hole” Style Attack

February 16, 2013 at 5:06 pm

In the CCNA Security discipline, we learn about many different security attacks. These include such common issues as Reconnaissance Attacks and the dreaded Distributed Denial of Service (DDoS) attacks. It is understandable that new day zero (brand new and unknown) attacks are always going to take place.

Want a real world example? Facebook just experienced some new day zero problems centered around a class of attack known as a Watering Hole attack. This is where a popular Web site used by an organization is attacked and is able to infect systems that visit that site. This is certainly a scary proposition, especially when you consider that Facebook computers that were infected were fully patched to protect against all known attacks.

Want to read the complete story? I hope you do – check it out here:

Wall Street Journal: Facebook – We Were Hacked But Don’t Panic

CCIE Security Lab Version 4 VPN Topic Checklist

February 15, 2013 at 9:16 pm

As I start back in my CCIE Security studies, I am going to start with the Lab items for VPNs – here they are:

  • Understanding Cryptographic Protocols (ISAKMP, IKEv1 and IKEv2, ESP, Authentication Header, CA)
  • IPsec VPN Architecture on Cisco IOS Software and Cisco ASA Security Appliance
  • Configuring VPNs Using ISAKMP Profiles
  • Configuring VPNs Using IPsec Profiles
  • GRE over IPsec Using IPsec Profiles

CCIE Security Lab Version 4.0 Equipment List

February 14, 2013 at 3:01 pm

One of the exciting and challenging aspects of the CCIE Security Version 4.0 Lab Exam is the fact that there are many important security devices and operating systems that we must master. Here is the list that we should be ready for.

Cisco 3800 Series Integrated Services Routers (ISR)
Cisco 1800 Series Integrated Services Routers (ISR)
Cisco 2900 Series Integrated Services Routers (ISR G2)
Cisco ISR Series running IOS Software Version 15.1(x)T and 15.2(x)T
We can expect about 6 of these routers

Cisco Catalyst 3560-24TS Series Switches
Cisco Catalyst 3750-X Series Switches
Cisco Catalyst 3560/3750 Series Switches running Cisco IOS Software Release 12.2SE/15.0(x)SE
We can expect about 6 of these switches