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Troubleshooting a Router Installation

I recently managed a router installation for a client and thought it would be helpful to share the issues I encountered, along with the techniques I used to overcome them..

In this case, we took a Cisco 2851 Integrated Services Router that was sitting on a shelf and turned it into a DNS proxy. Inevitably, when you plan an installation you will forget something. What separates a successful installation from a failure is how you deal with what you forgot. In the following video, you will see how I determined that the incorrect router port was connected as well as the wrong VLAN.

With this installation there were a few factors that helped the troubleshooting process:

  • The DNS proxy wasn’t in production and will be phased in, so it wasn’t critical that be up ASAP.
  • Even though the tech powered on and connected the router to the network and left, he would be back Monday morning to assist if needed.
  • I set up a computer with a console cable and had VPN access for testing and/or troubleshooting.

I can’t stress enough that you should have the access and ability to test during an installation outside of your fancy network management system.  The network analyst needs to have a good grasp of basic troubleshooting commands as well as a network diagram.