Category:   Cisco

This post represents the solution and explanation for quiz-7. The junior network administrator tried to update the configuration on a switch by enabling mls qos and immediatelly created an outage. See what happened !

This post represents the solution and explanation for quiz-6. Running dynamic routing protocols over tunnels can result in recursive problems. Read more to understand the problem and some solutions.

This post represents the solution and explanation for quiz-5.
It explains one of the Loop Prevention mechanisms in OSPF by using the P-bit in the LSA.

This post represents the solution and explanation for quiz-4. The quiz shows that, although the BGP speakers can reach each other, they do not establish an eBGP session. Read more to understand the problem.

This post represents the solution and explanation for quiz-3.
NAT on Cisco IOS can be pretty frustrating sometimes and it may take time and practice to master it.

This post represents the solution and explanation for quiz-2.
It shows one of the common problems, solutions and recommendations when implementing MSTP.

This post represents the solution and explanation for quiz-1.
It shows one of the common problems, solutions and recommendations when implementing MSTP.

After reading several forums with people arguing about what routers should be configured with the "ip pim autorp listener" command, I have decided to write this post explaining things in my own way (of course, with a lot of pictures, as usual).

On 3560 and 3750 series switches, there are several ACL types that can be used, each with its own features and restrictions. This post represents the second part covering VLAN maps.

On 3560 and 3750 series switches, there are several ACL types that can be used, each with its own features and restrictions. This post represents the first part covering Port ACLs and Router ACLs.

A pretty long post that summarizes the characteristics of OSPF protocol when using it on a CE-PE link. Read along to review its features, learn about BGP extended communities and loop prevention mechanisms for OSPF on CE-PE links.

Portfast + bpdufilter (used together) can be enabled globally or at interface level.
Although the first impression is that the only difference is the global or per-interface effect, this is not entirely true and another subtle and important difference is described in this post.

Welcome on my very first post on my new fresh technical blog!
This post shows different ways of how to match packets based on their length. While this may not be very common in real production, you will find it useful during your CCIE preparations.