VPCS(Virtual PC Simulator) is a PC simulating software which is small and easy to use. For the Dynamips user, this simulator is fairly handy.

While I was installing and configuring VPCS, I got error says "206-unable to create UDP NIO"

error message 206-unable to create UDP NIO


Last Updated (Monday, 21 September 2009 17:59)

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Cisco Express Forwarding (CEF) is well-known Cisco advanced Layer 3 IP switching technology. This technology brings traffic load-sharing technique that is functionality in a router that distributes packets across multiple links based on layer 3 routing information. It has two modes; per-destination and per-packet. As you know, per-destination is default setting Cisco gear by Cisco. Some of circumstance, load-sharing by per-packet mode would be desirable, but most of case per-destination mode would be the best choice. One of famous reason would be out of sequence order on the hi-speed link. This happening will dramatically reduce end-to-end performance.


Traffic ratio wise, the per-packet mode will utilize all involved circuits in exact equal amount of traffic while the per-destination mode utilizes circuits in vary.

To verify traffic load-sharing per packet, try below command


Cisco_router#Show ip cef exact-route x.x.x.x y.y.y.y


Last Updated (Monday, 21 September 2009 20:18)

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How to setup simple and basic Java development environment on home PC (Window XP). I hope this is informative for beginner or light Java users.

  • Download Java JDK
  • Download free editor
  • Setup path to JDK directory
  • Configure User tools

Last Updated (Wednesday, 15 July 2009 13:37)

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Sometimes, by looking over some basic or fundamental information during troubleshooting, we got wrong path and wasted hack of time. If you carefully reviewed interface status, you might easily guess what the root of issue. At least some of clue from there. Understanding interface status is very important step on your troubleshooting path.



Last Updated (Thursday, 25 March 2010 18:35)

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Vyatta is well known open source program for someone doesn't want to pay big bucks to top logo_vyatta.pngvenders of networking field. From Vyatta documentation, we can compare how much money you can save if you are using Vyatta instead Cisco or Juniper.

This article will share some experience of my first installation of Vyatta today. Latest version of Vyatta community version is 5.0, is called VC5. I had Ethernet interface recognition issue, but I couldn't find any good information to fix it. Finally, I tried few other ways to fix the issue.

Here is my server's specification: Dell1450 (/w SATA) two Quadcore Xeon CPU, 6G RAM and Broadcom NetXtreme E1000 card.  

Installation was easy enough, but Vyatta doesn't recognize my Ethernet card. I spent more few hours to find a solution to resolve the issue, but not much information out there. Finally, I found some way to address. Well, I don't like the way, but it works at least.

Last Updated (Thursday, 25 June 2009 20:24)

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Splunk was configured as a Syslog server on my lab network for few weeks now. Since I logo_splunk.pngmodified few parameters on service side and configured network devices, firewall, switches and router, which sent syslog message to the Splunk server. Past few days it built pretty thick index database. Well my index size is way below than 500Mbyte daily limitation for free version of Splunk. I am not expecting huge errors and critical messages because it is small Lab and also I am only monitoring network devices.

Today, while I was playing and reviewing Splunk, I found some of device within network sending spoofing traffic which is sending packet to unknown network, As far as I know I didn't set it up within the lab network.

Let's find out what's going on.

Last Updated (Thursday, 25 June 2009 20:23)

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