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One command that had a fairly long history first with the PIX Firewall and now the ASA is the shun command. In this post we’ll examine this command’s history, why it’s useful, and its new-found resurgence in threat detection implementation.
If you’re in IT, you’ve likely heard the saying, “In technology, the only thing constant is change itself,” and boy is that right! For technical companies, if you are not moving forward, then you’re falling behind. There is no such thing as standing still! A perfect example of this mindset is in Cisco’s evolution of video conferencing and telepresence.
In light of the recent tragic events in Haiti, it might be a good time to review some of the requirements for a well designed Uninterruptible Power Source (UPS) to be included in all of our critical network installations. As a CCNA, we are called upon to help maintai...
Interior Gateway Routing Protocol (IGRP) was a Cisco-proprietary Distance-Vector (D-V) classful routing protocol - basically an improved version of RIPv1. Like other D-V protocols, each IGRP router periodically flooded its routing table, but it differed from RIP in two ways. First, RIP’s advertisement interval was thirty seconds but IGRP’s was ninety seconds, which allowed IGRP to scale to larger networks than RIP. Second, RIP used a simple hop count metric, but IGRP’s more sophisticated metric was based on minimum path bandwidth and total path delay, with options to include link reliability and interface loading.
In 2013, Cisco released their Software Defined Networking (SDN) solution for the data center known as Cisco Application Centric Infrastructure (ACI). For many years, the networking industry has been asking for an approach to configuring networking devices more efficiently than having to individually configure each and every router and switch.
Moving data from one networked device to another requires several different functions. Each function has its own protocol or protocols that define how it is accomplished. Also, the process of delivering data from one device to another can vary. The main factor in data delivery is determining whether the two devices are directly connected or remotely connected.
Moving data from one networked device to another requires several different functions. Each function has its own protocol or protocols that define how it is accomplished. Also, the process of delivering data from one device to another can vary. The main factor in data delivery is determining whether the two devices are directly connected or remotely connected.
Like it or not, Internet of Things (IoT) is upon us. There are a number of factors that will impact its adoption rate, and the inevitable privacy (or lack of) discussions will likely happen sooner than later. This is going to change the world as we know it, in many cases for the better. But we will need to keep an eye on the extent to which it invades our personal lives if it is going to be the positive force it has the potential to be.
Cisco Access Control Lists (ACLs) are used in nearly all product lines for several purposes, including filtering packets (data traffic) as it crosses from an inbound port to an outbound port on a router or switch, defining classes of traffic, and restricting access to devices or services. Knowing how to design, configure, and troubleshoot ACLs is required for all network engineers working within a Cisco network.
While the Internet uses IP addresses assigned by an Internet authority such as the American Registry for Internet Numbers (ARIN), there are too few of these numbers to uniquely identify the millions of computers and computing devices in the world. Therefore, most enterprises use private addresses which allow them to identify the aforementioned computers. Of course, these IP numbers cannot be allowed on the Internet because all private networks use the same ones so there would be vast overlapping of addresses, and the addresses are not compliant anyway. Therefore, it is necessary to change the identity of a private host to a legal public host. This process is called Network Address Translation (NAT) and may be implemented on Cisco firewall products and Cisco routers. The firewall device(s) at the Internet demarcation point is by far the more popular way to implement NAT, but routers are used in small offices or small-to-medium-sized networks in which a separate firewalling solution is not possible or affordable. The focus of this paper is on the router-based NAT solution.