Back to Basics: How to Rack a Switch
It is quite commonplace these days to see equipment mounted incorrectly in a rack. Even though we are not mechanical engineers, it is beneficial to understand the principles behind the parts of our jobs ruled…
Articles by jkerns
Network Documentation Series: Port Mapping
In this post, I will be doing a brief commentary on creating and maintaining a physical port mapping spreadsheet. A port mapping spreadsheet is useful for keeping track of used/available ports on your network equipment,…
Network Documentation Series: Logical Diagram
In this article, I will do a walk-through of a logical network diagram. As I also said in the Physical Diagram article: I prefer to use the term “logical” instead of “L3” because it is…
Network Documentation Series: Physical Diagram
This article is a quick tutorial for creating and maintaining a physical network diagram. I prefer to use the term “physical” instead of “L1” because it is more easily understood by somebody unfamiliar with the…
Network Documentation Series: Preamble
This post is the first in a series of articles tackling the topic of creating and maintaining proper network documentation. Each article will include a file which can be downloaded and used as a template…
Cisco NAT Cheat Sheet
I’ve always had a difficult time when attempting to remember how to implement the different types of NAT available on ASA and IOS devices. It doesn’t help that between the two device families, there are…
CDP on an ASA (To Some Extent)
If you have been in the Cisco networking world for any length of time then you have probably used CDP (Cisco Discovery Protocol) or LLDP (Link Layer Discovery Protocol) at least once or twice to…
SDN – Is Software Fast Enough
During a VMWare NSX training class a while back, a question was raised to the instructor concerning the throughput that is possible on a NSX distributed switch or router (two components that are crucial to…
ASA Dual ISP
When it comes to internet redundancy, the Cisco ASA family of firewalls can be very flexible in how they can be configured to provide that highly available connection. You can even host highly available internet-facing…
VRF-Lite, MPLS, and Null Routing
In the field of IP routing, the practice of using null routes (A.K.A. “Black-Hole Routes”) has always had a place. Null routes are often used for DOS mitigation, loop prevention, routing stability, and route summarization….