Month: March 2009

Cisco security updates squash router bugs

CiscoCisco has released eight security updates for the Internetwork Operating System (IOS) software used to power its routers.

The patches were released Wednesday, the day Cisco had previously scheduled for its twice-yearly IOS updates. None of the bugs had been publicly disclosed ahead of Wednesday’s updates, but some of them were reported to Cisco by outside sources.

Most of the bugs could be exploited by attackers to crash or somehow disrupt service to a router, typically if a specific, vulnerable service is enabled, Cisco said.

The eight updates fix 11 security vulnerabilities, according to Jean Reese, senior manager with Cisco’s Product Security Incident Response Team.

Read the full article on NetworkWorld.com…

Vote Earth! Switch Off Your Lights For Earth Hour

This post has nothing with tech section…or maybe everything!

earthhour_335x500Cuddling up with your loved ones and admiring the stars in the night sky or organising a treasure hunt in the dark? At 8:30pm on Saturday 28 March, people from all corners of the world will turn off their lights for one hour – Earth Hour – and cast their vote for action on climate change. Anybody can participate and join together with millions of people across the globe celebrating Earth Hour.

Earth Hour is about taking simple steps everyday that collectively reduce carbon emissions – from businesses turning off their lights when their offices are empty to households turning off appliances rather than leaving them on standby.

Here are 10 different ways to spend Earth Hour and reduce your carbon footprint:

1. Attend a local Earth Hour event or organise your own by throwing an Earth Hour street party with your neighbours
2. Gather family & friends for a night picnic in your local park and look at the stars
3. Enjoy a family dinner by candlelight
4. Organise a treasure hunt in the dark
5. Take the dog for a night walk
6. Have a candle-lit bath
7. Sit in the dark and share stories
8. Organise a family night playing board games
9. Share a romantic night in with your loved one
10. Upload your ‘on the night’ photos and videos to flickr and YouTube respectively, and then add them to the Earth Hour flickr group and the global YouTube Group.

Earth Hour Executive Director, Andy Ridley, is encouraging people to participate in whatever way they choose and to think beyond the hour.

“There are no hard and fast rules surrounding participation in Earth Hour. We only ask that you flick that switch and have fun doing whatever you choose to do during that time.

Make Earth Hour work for you. Families with young children should feel free to turn their lights off earlier than 8:30pm and for those having too much fun in the dark during the hour, don’t feel you have to limit yourself to one hour and switch back on at 9:30pm.”

To find out more about Earth Hour, visit the official website www.earthhour.org, sign up and join millions of people in more than 1,400 cities and towns in 80 countries throughout the world by turning off your lights for one hour at 8:30pm on Saturday 28 March.

Note: Original post from EarthHour.org



How to integrate GNS3 with Virtual PC

In this article I want to show you how to extend your posibilities to test a network in GNS3. Sure, it’s simple sometime to use a Loobpack interface on one of your edge routers to simulate an external network, but sometime is useful to have something connected to the router port. Take as an example QoS marking and classification. If you want to mark something inbound, then you need a connection to the router port where you want to mark the packets.

Additional to my example here, which include Virtual PC Simulator, you can find useful tutorial about GNS3 and VMware integration on  gns3-labs.com or how to emulate a voice lab with the same tools on blindhog.net.

Even most of you are familiar with GNS3 and maybe Virtual PC Simulator, let me begin with some short description about this 2 software.


GNS3 is a Graphical Network Simulator that allows emulation of complex networks. It allows you to run a Cisco IOS in a virtual environment on your computer (running Linux, MacOS X or Linux). GNS3 is a graphical front end to a product called Dynagen. Dynamips is the core program that allows IOS emulation.

The Virtual PC Simulator (VPCS) allow you to simulate up to 9 PCs. You can ping/traceroute them, or ping/traceroute the other hosts/routers from the virtual PCs when you study the Cisco routers in the Dynamips. VPCS is not the traditional PC, it is just a program running on the Linux or Windows, and only few network commands can be used in it. But VPCS can give you a big hand when you study the Cisco devices in the Dynamips. VPCS can replace the routers or VMware boxes which are used as PCs in the Dynamips network.

Before we start, I assume that you already have these tools installed. If not, please download and install GNS3 and VPCS.

On the following example I will show you how to configure a network topology including 2 Virtual PCs and one router and how to interconnect them in GNS3. This presentation is simulate a basic network, but after you learn how to do it, you can configure more complex one. You can have a look to the topology to understand better what I’m talking about.

Please see the video presentation below:

gns3-virtualpc

Other bloggers article that you might be interested in:

What it will take for mobile VoIP to get enterprise-ready

voipBy all rights, mobile VoIP sounds like an enticing proposition for a lot of companies.

After all, what enterprise wouldn’t jump at the opportunity to save money on their mobile phone bills by sending their wireless calls over an IP network rather than a cellular network? But despite this attractive premise, current mobile VoIP technology has yet to evolve to the point where users can simply switch on their phones anywhere and expect to connect to a secure IP network.

The obvious reason for this is because mobile VoIP devices today are reliant upon Wi-Fi technology, which can offer quality voice service but which also has limited range and is prone to coverage gaps that make it problematic as a voice technology. These factors have so far limited mobile VoIP offerings to office environments or home environments where workers can securely connect to local hotspots to get a dedicated voice channel. But Stan Schatt, an analyst at ABI Research, says that these in-office, in-house technologies have not yet matured enough to the point where they can properly support more complicated applications such as conference calling.

Read the full article on NetworkWorld.com…

10 tips that I can tell you about Cisco CCIE exam preparation

10 tips Since now I’m closer than ever to my CCIE lab exam, I thought that it would be a good opportunity to share some of my preparation experience with you. Even if this post is focused of the CCIE preparation, I believe that you can take my advices into consideration even if you are preparing for some other exam.

As most of you, when I started the preparation I searched on the Internet about some advices like what should I read, how much time to dedicate to study and how to achieve the maxium results. This are only a few example, the entire list is much more longer and boring I believe.

I found a lot of tips, tricks, advices and many more. Some of them were really useful and helped me, but a lot (and I mean a lot) had no idea what they are talking about. I was dissapointed to find out that some advices there were just lines on a web page and the author had no idea what he or she was talking about, just taking the ideas from another blog (usually one which belong to a network engineer) and posting on his or her blog, webpage article.

So, why I’m writing this post. Well I hope that the way I see things and the advices that I give based on my personal experience can really help some of you.

Don’t trust everything and everybody – If somebody tell you that you should read at least xy number of books and take 1-2-3 bootcamps, stop one second and think. Compare your experience with the one of the person you are speaking to. Maybe you have 7-10 years of experience in related field and you already know most of the theoretic things. Don’t spend time reading just because somebody praise himself on mailing list or some forum with how many materials he read.

Don’t get discouraged – If you are reading on Internet (e.g. forum, mailing lists) ideas  that get you discouraged on and on…quit reading them; YOU are the only one aware of your knowledge and you have to trust yourself not opinions on the Internet. Just because somebody say that you will fail on your first attempt, does not mean that it will be like that.

Do not learn if you are tired – You will only get more tired and more frustrated. Do not compare the time you are learning with the one of other CCIE pretenders. You don’t have to learn 12 hours / day just because somebody does it. Maybe that persons has not other thing to do, no work, family, pets  or he / she are more slow learners than you. It’s not a competition who’s learning more in a day. If you are tired after a work day, just go to bed, sleep and then when you can you will learn. You’ll see that you can learn in 2 hours when you’re rest more that in 4 hours when your tired.

Don’t quit, just relax – If you encounter some problems during your lab preparation, and you just cannot see the solution, take a 30 minutes break, and maybe than you can see the task with “different eyes”. Sometime the solution is just in front of you, but you cannot see it right away.

Trust your knowledge – I’m not saying here to solve one lab or task during preparation and to praise yourself being so smart, but the right imagine about you can help. Remember that the more trustful you are in our skills, the more chances to obtain a positive results you have.

Don’t hesitate – When you are doing labs, task, questionnaires usually the first idea you have is the best one. Analyze the request correct but don’t start questioning yourself if are doing well, maybe you should apply other solution, or maybe…all of this will confuse you and give you headache. At least now you are in preparation and you can check if you are thinking in the right way. Also you can learn from your mistakes.

When you are not learning try not to think that you should do it – This is one of the most hard thing to achieve, and I have to admit that in most of the time I cannot follow this advice. But if you can, do it. As an example, you really want to see movie, you go to the cinema, but your mind is just making you think of networking, topologies, cisco and so on…At the end you will see that you did not enjoy the movie at all, didn’t relax and didn’t learn either. You gain nothing.

Do not neglect your closer ones during preparation – You will see that you have much more to earn if you give up 1-2 hours of learning in weekend and get out with your family, girlfriend, friends or pet. Try to understand that you have more to gain from their support sometimes than from those 2 extra hours of learning.

Prepare yourself – In a consistent and rigorous mode. After all any exam and especially Cisco CCIE exams are hard to pass. This kind of exams can really improve your professional and personal life.

Be kind and share knowledge to those who are in need – You never know when somebody will return the favor to you. I’m not saying here to let somebody (even more if that somebody is making money from your help) to take advantage of you, but helping make you feel better and prove to you that you didn’t learn for nothing.

Maybe you expected more technical advices and tips and you are a little bit disappointed, but I can assure you that the lines above can really help you in your preparation. Nothing is more important that to understand that CCIE exam is design to help you improve your life not destroy it. If you neglect everything in favor of preparation and then you have bad luck and do not pass it from the first attempt, you could become frustrated because you’ll realize that you spent a long time just learning and now you have nothing. This will stop you from going to the second or third attempt and you’ll end with lost time and without any degree.