In a previous blog I discussed running EIGRP named mode in GNS3. In that blog, I promised to dig a little deeper into how the results of the computations were reached. I have published a couple of blogs which strive to display the classic formula in human friendly form. I will attempt the same thing … Continue reading Understanding EIGRP named mode wide-metric computation
I recently posted a blog (How to configure gateway redundancy with HSRP in IOS) about how to configure HSRP for gateway redundancy. In that blog I mentioned that there is an alternate protocol which performs the same functionality as HSRP, but it is not Cisco-proprietary. This protocol is Virtual Router Redundancy Protocol (VRRP). Figure 1 … Continue reading How to configure gateway redundancy with VRRP in IOS
So you are moving from a small network to a medium network. Now it matters if the path from your clients to your default gateway is down. Or even more crucial, it matters if your clients’ default gateway can get them to external networks (such as the Internet). How can this be done? With a … Continue reading How to configure gateway redundancy with HSRP in IOS
Do you have a 3560 switch and you want to run EIGRP for IPv6? Have you typed ipv6 router ? and you don’t even see eigrp as one of the options? I did some research on Cisco’s feature navigator in response to some students’ questions on this topic and discovered that the 3560 switch DOES … Continue reading How to configure your Cisco 3560 MLS to use EIGRP for IPv6
If you are keeping up with Cisco’s announcements regarding EIGRP, you are aware that Cisco has released their proprietary routing protocol into the open. However, one of the pieces they are keeping close to the vest is the stub feature. If your environment has need of this functionality, this blog may enlighten you as to … Continue reading Understanding Cisco’s EIGRP Stub Router Feature
Have you ever wanted to make your router dance on the head of a pin? Neither have I. But that doesn’t mean I don’t want to modify its default behavior from time to time either. Since routers already have a default route selection process, we do well to understand it so we can manipulate it … Continue reading Understanding the DISTANCE command on Cisco Routers
If you were to ask a number of networking professionals how routers make forwarding decisions, you might hear one answer far more than any other – Administrative Distance. In simplest terms, Administrative Distance (AD) is a ranking of believability. That is, if I am a router with more than one routing protocol running, to whom … Continue reading To Cisco Routers, This Concept Is Number One!
In previous blogs I have covered both ip prefix lists and route maps How to interpret Cisco IP prefix lists and How to Decipher Cisco Route Maps. Now I want to take some of what has been discussed and make a useful application to an actual network scenario and router configurations. Let’s say I have a … Continue reading How to redistribute routes using Cisco route maps and IP prefix lists
How many times have you heard that two potential EIGRP neighbors with md5 authentication configured will neighbor up even if they are not using the same key in their key chains? Several Cisco texts have made this comment. I decided that I would put this to the test. I configured some real routers and I … Continue reading Cisco EIGRP authentication – what is the key?
As you may know if you read my blogs or have been in my classes, I am a big believer in memory aids, or mnemonics. I have a previous blog; Cisco certification exam memory aids – My favorite mnemonics which lists a few of them, but the list is always growing. One of the things … Continue reading More Cisco CCNA Certification Study Tips and Aids