The order of operations is hard coded into Cisco IOS and tells the router how to process traffic according to the configuration of different router functions and features. While we cant’ make you think like a router, it is likely you have already picked up on some of these. When configuring features such as Network […]

What is NBAR?  NBAR is a powerful packet filtering/identification/firewall that you may already have installed on your Cisco router. For a list of what NBAR can detect look here. NBAR is also what we call Cisco’s “autopilot” for QoS. It has been in IOS since ver. 12.0 and has been continually updated with recognition of

As we said in our basic ACL How To, ACL’s’ are vital to networking today. Everyone uses them, and proper usage is imperative. In this How To, we are going a little deeper into two ACL types: Intrastructure and Transit.  We will discuss the two with examples and you will clearly understand the difference between

ACL’s’ are vital to networking today. Everyone uses them, and proper usage is imperative. Besides being difficult to use at times, the penalty for an ACL mistake is huge. In one swift swoop, you could incorrectly permit malicious attackers onto your network or incorrectly deny all valid users from your network. Either way, the consequences

What is AAA? It stands for Authentication, Authorization, and Accounting. When it comes to network security, AAA is one of many features a network manager may use. Here is what each of these are used for and why you should care: Authentication: Identifies users by login and password using challenge and response methodology before the

This How To explains how to fix an annoying default behavior on Cisco IOS. Mistype a command on a Cisco router and the router thinks you just typed a hostname. This is often an annoying problem. For example: Router#shwoTranslating “shwo”…domain server (10.1.1.1) % Unknown command or computer name, or unable to find computer addressRouter# Here,

This How To explains the fundamentals of configuring EIGRP.  EIGRP is an advanced distance-vector routing protocol that is used on a computer network to help automate routing decisions and configuration. The protocol was designed by Cisco Systems as a proprietary protocol, available only on Cisco routers, but Cisco converted it to an open standard in

When a router has to forward a packet, it looks in its routing table to match as many bits as possible of the destination address to a route in its routing table.  This is known as longest match routing. Once a match is found, the router forward the packet to the next hop defined by

What happens if there is a system or user on a VLAN that is infected by malware or is deliberately running a scanning program?  This can cause a massive amount of entries in the CAM Table of the switch.  Think of the CAM table as the MAC address table.  There is a certain limit of