While RIP is not used for the ‘real’ Internet routing, and hasn’t been for many years, we often use RIP to do testing as it is so quick and easy to configure the protocol. Also, if you are learning shortest path routing for the first time, RIP is a great place to start as it […]
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This How To addresses the method of limiting bandwidth on ports of a Cisco Switch or Router. Why should you limit bandwidth? There are a number of reasons for limiting bandwidth on a Cisco switch Ethernet port. For example, let’s say you work for an Internet service provider in a colocation facility, and you sell
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In our high level overview of QoS we stated that configuring QoS can be complicated. Cisco developed NBAR as the QoS ‘autopilot’ as one solution to this problem. More recently, Cisco has developed something called AutoQoS, which also configures QoS settings for you. You can use AutoQoS to a)create policies based on real-time traffic flowing
Generic Route Encapsulation is a tunneling technique in IP networking where a received IP packet is re-encapsulated in a second IP header (IP-in-IP) and sent across the network. It is like a Layer 3 VPN but alone it is not a secure VPN. You can encrypt GRE with an encryption protocol such as IPSec to
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This How To covers something called Black Hole Routing using the NULL interface in Cisco IOS. The entire YouTube network went down in 2009, across the globe, for about two hours — thanks to a mistake made by an ISP in Pakistan. That mistake involved a black hole route accidentally distributed around the world. While
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If you routinely have to change or modify your Windows configuration, especially for things like printers and networks, you find yourself navigating the Control Panel maze of choices to get to the place where this can be done. This can become tedious and time consuming. What if you had a place where all these types
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In the prior articles (Getting Started with nmap and Deeper Scanning with nmap), we showed you how to get started, and how to dive deeper with this superb network scanner. Let’s go even deeper! One of the cool things nmap has is the ability to create scripts. Now doing this from scratch would be
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In my prior article on getting started with nmap, I showed you how to get started with this superb network scanner. In that article we did basic scans to locate what hosts were on a given network and display what services were running on those hosts. In this article I am going to dig a
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Welcome to my little nmap cheat sheet! To learn more about nmap – check out my articles: Getting Started with nmap and Deeper Scanning with nmap and Even Deeper Scanning with nmap and Advanced nmap Scripting Engine. There was no intent here to recreate the full nmap capabilities, that would have been a waste of your and
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Nmap (“Network Mapper”) is a free and open source (license) utility for network discovery and security auditing that has been around since 1997. Surveillance and network scanning is often one of the first steps in Penetration Testing or Security Validation. Many systems and network administrators also find it useful for tasks such as network inventory,
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In this How To we will explain the basics of SSH configuration on Cisco IOS. To start, we recommend you verify you have the correct IOS version that supports triple-DES and SSH. With that said, let’s jump in. First, make sure your router has a hostname by using the hostname command. Here’s an example: Router#
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A common misunderstanding with configuring Cisco routers is the meaning of the ‘bandwidth’ command. Following a recent discussion we had with a client we thought it appropriate to add some specifics to our Tech Tips area. Let’s say you have a serial interface between two Cisco routers and the interface is up and running with
The Web Cache Communications Protocol (WCCP) is used to redirect traffic (usually Web page requests) to another device in real time. The most common use for WCCP is redirecting Web traffic to a server that provides Web caching, filtering, or other services. You can enable WCCP on your router, but you should only use WCCP
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In this How To we will introduce the concepts of Quality of Service or QoS (kwas). Managing QoS is an important process and skill that everyone who runs a network needs to understand. We will introduce you to QoS principles at a high level. You will find details in other How To’s. First, lets understand
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Have you ever loaded a router with IOS that is too big for memory? If you have, then you have ended up in a problem and the router dumps you to ROM Monitor or ROMMON prompt. In this How To we weill explain what to do. There is a simple way to reload the router
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