Tutorial: IPv6 Tunnels Part 2 – Automatic 6to4 Tunnels

In our previous article on IPv6 tunnels, we looked at manual GRE and IPv6IP Tunnels in order to provide connectivity for IPv6 networks segregated by an IPv4 network. By tunneling IPv6 over IP, we can migrate our internal networks to IPv6 and still have communication between these networks, even though we are seperated by an IPv4 network. In this article we will be using another method to provide connectivity for IPv6 networks segregated by an IPv4 network: The Automatic 6to4 Tunnel! Mastering IPv6 is not only an important part of a CCIE candidates journey, but will become increasingly important as the global pool of IPv4 addresses diminishes….

Accessing your console lines with Reverse SSH

Greg Ferro from My EtherealMind has a great article on IOS Reverse SSH console access. We use reverse telnet access here for all our lab equipment access and I always wondered (but never had time to investigate) whether we could do reverse ssh. Looks like I’ve just given myself more work to do. Thanks [...]

U.U.U Ping Response

Ever wonder why you get a U.U.U ping response time instead of a UUUUU for icmp unreachable messages? Well wonder no more! Packetlife has a great article dissecting the U.U.U ping response. I knew about icmp rate-limit but I never put two and two together before reading the article. Awesome!

Internetwork Expert Twitter

Looks like Internetwork Expert has set up a twitter account. You can follow them here: http://twitter.com/InternetworkExp

Tutorial: Time-Based ACLS

Time based ACLS are useful when you want to restrict traffic based on time of day. For example, you might employ time based ACLs if you wanted to only allow web surfing during a particular time of day or allow access to a server during work hours. We will be exploring these scenarios in this tutorial.

Lots of Dynamips / Dynagen Sample Lab Topologies

I was browsing through my collection of resources and I found a great collection of sample Dynamips / Dynagen topologies to play around with. You can download most of the common lab topologies from the various training vendors as Dynagen .net files. This would be an awesome collection of resources for someone studying for Cisco [...]

Awesome Collection of Cisco Links

Michael Morris has updated his blog on NetworkWorld.com with a HUGE collection of useful cisco related links. Found a few gems in there!

Blog: My CCIE story….

I have been waiting to write this post. I am just so deliriously happy right now. Before I start, I want to thank my beautiful wife for her support. She was that voice I heard in my head that told me to just keep going, and never give up when I’d lost hope. I’m glad [...]

CCIE #20716

I passed. I’m so happy right now. :)
I’ll post a full write up later…time for a scotch or three!!! CCIE #20716…has a nice ring to it!

Blog: Coming up for air…2 days to go

Okay, in the last week I have redone Mocklabs 3,4,5,6, and 7, Workbook2 Lab 8, Workbook 3 labs 7, 8 and 9. I’m done with labs. :) I was mainly focusing on speed because there wasn’t anything on those labs that I hadn’t seen before. At this stage, I’m pretty exhausted and I think I [...]

Victor Cappuccio Passed!

Looks like another one of the bloggers I read regularly has passed: Congratulations Victor Cappuccio CCIE#20657! Man, all these CCIE bloggers passing…not that I didn’t feel enough pressure already! :)

Internetwork Expert Brainteaser #1 Solution

Richard Bannister has proposed 4 solutions to the Internetwork Expert Brainteaser. They are great examples, especially on how to match certain fields of a Layer3 packet using Cisco Flexible Packet Matching (FPM).

Ethan Passed!!! CCIE #20655

Head on over to Ethan Banks blog and congratulate him on getting his CCIE! That is awesome news. Well done Ethan CCIE #20655!

List of Configuration Registers and what they do…

Here is a list of all the configuration registers that you can use in ROMMON and what they do.

Blog: 10 Days to go…Last Mock Lab Done!

“Knowing is not enough. We must apply.” -Johann Wolfgang von Goethe.

I just finished Mock Lab 7 which is the hardest of the Mock Labs. I should probably rephrase that…it is the Mock Lab with the highest difficulty rating. I actually thought this one was easier than Mock Lab 4 (which is the spawn of satan! lol). I answered everything. There were plenty of tricky questions but each question was fairly independent of the others so if you stuffed one up, it didn’t really effect any other question. Couple of things I had to figure out because I had never done before, but that is where the DocCD really helped.

DocCD Reading List

I was putting together some notes on what DocCD chapters I should read and I found this from Internetwork Expert: CCIE R&S DocCD Recommended Reading List. Now why didn’t I know about this before!? :)

Troubleshooting: IP Addressing Tricks & Tips Using PPP

Let’s say you have this scenario: R4 and R5 are connected via a serial cable. Configure IP Addressing so that R4 and R5 are in the 192.168.45.0/24. R4 should have an IP of 192.168.45.4/24. R5 should have an IP address off 192.168.45.5/24. The catch: Do not configure an IP Address with the ip address 192.168.45.4 255.255.255.0 command directly on R4’s s1/1 interface. Let’s have a look at the different ways we can solve this….

NetKit – Full Network Emulation on Linux

Just found about NetKit thanks to a follower on twitter (I’m starting to love twitter!).
“Netkit has been conceived as an environment for setting up and performing networking experiments at low cost and with little effort. It allows to “create” several virtual network devices (full-fledged routers, switches, computers, etc.) that can be easily interconnected in [...]

Blog: Mock Lab 4 is the spawn of Satan!

Mock Lab 4 is the spawn of Satan! lol.

*sigh*. I know I stuffed that one up. I just finished it. Didn’t have much time to check anything. I got full connectivity, and answered most things. I think I got something fundamentally wrong in the IGP section. I got to the end, and i was utterly exhausted. I’m sure I made mistakes, but I will see how it goes.

New Version of Dynagen Out!

Version 0.11.0 of Dynagen has just been released. The Dynagen tutorial has also been updated with info on how to set up PIX emulation. This is great news for those preparing for their security CCIE (and for those of us who want to play!). Check out the release notes here.

Blog: 17 days to go….

I spent this morning going through Mock Lab 6 again. I booked a 6 hour lab session and gave myself a challenge of completing the whole thing in those 6 hours. I just managed to do it (with a few minutes to spare!). I had spent the greater part of Thursday and Friday going through it thoroughly, analyzing it, trying out different things and multiple solutions. I figured out a couple of things that I stuffed up the first time.

Repeating labs definitely helps. I tend to do a lab now repeatedly until I know it back to front. A lot of people have said “what is the point of doing a lab over and over again, you just end up memorizing it”. This is true in some respects, but what I tend to do is go through the lab again until I don’t need to look up the answers for that lab.

Tutorial: BGP Conditional Route Injection with inject-map

One of the great new features that was introduced in IOS 12.3 is BGP conditional route injection. With conditional route injection we can insert more specific routes into a BGP table based on the existance of another route. Most of the routes in the current internet BGP table consists of aggregate routes. This is used to minimize the size and number of routes in global BGP routing table. The aggregation of routes can sometimes obscure more specific and accurate routing information. Wouldn’t it be cool if we could control and “un-aggregate” those routes on demand? Well that’s kinda what BGP conditional route injection does. It allows us to originate a more specific prefix into the BGP routing table based on an existing aggregated route.

Blog: CCIE Assessor Lab B

I got 70%. Pretty disappointed about this one, as I missed some easy masks. Some I lost because of the grading again looks for very specific answers (although I think this grading script was better than the last one).

Blog: Doc CD Issues and fixes

It looks like even if you don’t have access, or you think you might require access to a DocCD resource that is missing, the proctor is able to give you access to those missing/broken links. This was from the proctor in the Sydney lab as well, so that is a bit of a relief. I am still going to make sure I know how to find the information on all the versions of the DocCD, but it is still nice to know.

QOS: Configuring Policing using the access-list rate-limit command

Let’s say you have a scenario that says we want to configure R2 such that all inbound traffic marked with an IP precedence of 5 and 3 should be limitied to a maximum of 1Mbps. Anything above this rate should be discarded.

Sounds simple enough. What are the different IOS tools that you can accomplish this?