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How to configure an IPv4 GRE tunnel to carry IPv6 traffic

Continuing the review of the TSHOOT Topology, on the IPv6 network map there is a GRE tunnel that is configured between Router 3 and Router 4. This tunnel is in place to allow IPv6 traffic to traverse the 10.1.1.8/30 IPv4 network. So, while reviewing the IPv6 tshoot topology, I decided to try out the tunnel configuration.

There are several ways to configure tunnels to allow IPv6 traffic to traverse IPv4 networks (and vice versa). This post will be focusing on a GRE tunnel configuration. If you want to review the other ways to create tunnels, i.e.  Automatic IPv4-Compatible IPv6 Tunnels, IPv6 Rapid Deployment Tunnels, and Automatic 6to4 Tunnels, I've included a link below to a great resource on Cisco's website that shows some great examples of other tunnels.

I threw together the following network diagram to provide a visual of what we are configuring: 

IPv6_GRE_Tunnel2

Cisco SG100-16 Unmanaged Switch

Need more Gigabit Ethernet? Don't need it to be a managed switch? This 16 port 10/100/1000 Cisco switch might be a quick and easy solution for you.


B003AVN1PM_3

The Cisco SR2016T 16-Port Rackmount 10/100/1000 Gigabit Switch (A.K.A. SG100-16) is currently listing for below $200 USD and has several appealing features:

How to configure a Cisco router to be a frame relay switch

If you are studying for the TSHOOT exam, it is a good idea to familiarize yourself with the topology. I've been working on creating a lab that mocks the TSHOOT topology, and it has forced me to recall how to setup a Cisco router to act like a Frame Relay switch. 

Here is the topology that I've built. As you can see, it closely resembles the topology that Cisco has provided on their site. Since their doc doesn't provide specific DLCIs, I've used the most logical numbers I could think of.

tshoot-wan

The first step in configuring a Cisco router to act like a frame relay switch is to enable frame relay switching:

End of Life Announced for Cisco 7200 NPE-G1

Cisco this week has announced the end of sale and end of life dates for the 7200 Series NPE-G1 Network Processing Engine. This is an older routing engine that is definitely showing its age compared to newer platforms that are available.

The last day to buy the NPE-G1 is February 27, 2012. Last day for hardware support is February 28, 2017. The recommended upgrade path is the ASR1000 series.

Full details are available in the official announcement.

Windows 8 to include native support for ISO and VHD files

Just read an msdn blog post that reviews a cool feature to be included in Windows 8. Windows will now natively support ISO and VHD files! This is definitely nothing new, as 3rd party utilities have been available for years to provide this functionality in Windows. Alternatively, Linux has had the ability to mount ISOs since the dawn of time.

The good news is you will no longer have to go through the trouble of installing a 3rd party app, it'll just work.

Juniper's Tesla Motors Commercial

I realize this is a Juniper commercial, but the car is so cool I have to share. Check it out...

Free Cisco Press Chapter - Configuring Policies, Inheritance, and Attributes

Studying for your CCNP Security? If you are, or if you simply want to learn more about VPNs, take a look at this free chapter from Cisco Press on Configuring Policies, Inheritance, and Attributes.

This is straight out of the CCNP Security VPN 642-647 Official Cert Guide. According to Cisco Press, the chapter covers the following topics:

  • Policies and Their Relationships
  • Understanding Connection Profiles
  • Understanding Group Policies
  • Configure User Attributes
  • Using External Servers for AAA and Policy Assignment

Give it a read if you got your certification cross-hairs fixed on the CCNP Security.

Cisco Power Calculator

If you are ever designing a network or deploying a new switch that will be providing Power over Ethernet, be sure to check your power draw with the Cisco Power Calculator (CCO login required):

http://tools.cisco.com/cpc/LU.cpc

You start by selecting the type of switch you are deploying. Then you can choose how many of each type of device you will be plugging into your switch and it will tell you how much power will be required.  Here is a sample of some of the devices they let you choose from:

  • 7961G-GE - 0.3071 amps (12.9W)
  • AP-1200 with a+g radios (12.4W)
  • CP-7971G (14.9W)

Also, if you are deploying non-Cisco phones or APs, there are several IEEE compatible devices listed toward the bottom of the list:

CCNA Official Cert Library, 3rd Edition

The latest and greatest CCNA Certification Library is available for pre-order. The seasoned author, Wendell Odom, has updated the material from previous releases with new content and exercises.

In addition to the books to prep for ICND1 and ICND2, the library includes a test prep engine, a network simulator, and videos. With 1500 pages included, this package is a great resource for anyone starting out on their CCNA journey.

The library package is scheduled to be available October 14, but you can pre-order today.

Modify Windows Server Password Policy

So, while playing with Windows Server 2008 R2, I found the minimum password requirements to be a bit too stringent for a lab environment. If you find yourself in a similar predicament and wish to lower the password requirements to near-nothing (not recommended for production environments), then follow these steps:

How to convert an IMG file to ISO using Mac OS X Disk Utility

If you are ever in a situation where you have an img (disk image) file, but you want it to be an ISO file so you can mount it rather than burn it, then we have something in common. I stumbled on a quick and easy process using the free Mac OS X Disk Utility (free if you have a Mac) and have created a quick video to demonstrate the steps. Check it out...

Update: Thanks to an anonymous commenter, the much simpler way to achieve the same results is to rename the file extension from img to iso. I just tested this and it appears to work. Who would have thought?

Implementing Netflow - ip route-cache flow vs ip flow ingres

If you have ever implemented NetFlow, you may have noticed there are different commands available under interface configuration mode to enable collection. If you aren't sure what the different is between ip route-cache flow and ip flow ingress, here's the simple explanation:

To enable flow collection on a whole interface (including sub-interfaces), use:

ip route-cache flow

To enable flow collection only on a specific sub-interface, use:

ip flow ingress

Free Cisco Press Chapter - Designing Voicemail Systems with Cisco Unity Connection

Cisco Press has been nice enough to offer us all a free chapter from the book Cisco Unity Connection.

The chapter covers the following topics:

  • Design Considerations: Understand the capability of Cisco Unity Connection as it pertains to current users, network design, codecs, voicemail ports, and projected growth.
  • Active-Active Cluster Pair: Explore the high availability and redundancy feature of Cisco Unity Connection using the active-active cluster pair configuration.
  • Voice-Messaging Design: Design the voice-messaging system using Cisco Unity Connection platform overlays by determining the proper server sizing, equipment, codec, feature, and capabilities.
  • Voice-Messaging Networking: Understand the various networking options available in Cisco Unity Connection version 8.x software.

CEF Troubleshooting Commands

Whenever you are faced with troubleshooting a routing problem and the routing table looks normal, don't forget to check CEF. Cisco Express Forwarding (CEF) has been enabled by default for quite some time on most Cisco routers and has been known to cause issues from time to time.

I've created a list of a few of the most common (and a few not so common) CEF show commands that can help you track down a problem. Let's start with the basics - the FIB and the Adjacency table.

Forwarding Information Base (FIB) - This is a table that the router builds based on the routing table, but it's not the same thing as a routing table.  It contains the same forwarding decision information, but where the routing table would be like an encyclopedia of where to send packets, this is a cheat sheet.

Adjacency table - This is a table of all the layer 2, next hop information for the entries in the FIB.

How to change Windows Explorer default view to My Computer

If you have upgraded to Windows 7 from previous versions of Windows, you may have noticed a subtle difference when you open an explorer window – you see Libraries instead of drive locations. This was a subtle enough change that I didn’t really notice it for quite some time, I just knew that every time I opened explorer, I was looking at a completely useless view of folders.

So, I set out to find a way around this and Microsoft has kindly documented the procedure. For your convenience, I have shared the steps I followed below.

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Dr. Radut