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I recently came across an opportunity to use a relatively new feature in Cisco Unified Communications Manager (CUCM). Suppose you are the telecom administrator at a community hospital. During business hours, the Facilities Department is staffed and team members simpl...

As is sometimes the case, the idea for this article originated with a student question I received during one of the Securing Networks with ASA Fundamentals classes I have taught this summer. The course material mentions a simple scenario whereby IP Telephony traffic...

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.

This week’s post highlights some of the features and implementation specifics regarding the Datagram Transport Layer Service (DTLS) protocol used in Virtual Private Networks with the Cisco AnyConnect^® SSL client. I’ll provide some background as well as some screenshots and supported CLI commands.

An attacker needs to destroy evidence of his presence and activities for several reasons like being able to maintain access and evade detection (and the resulting punishment). Erasing evidence of a compromise is a requirement for any attacker who wants to remain obscure and evade trace back. This usually starts with erasing the contaminated logins and any possible error messages that may have been generated from the attack process.

Michael Scarborough details the debate how many discrete processes ITIL describes. The ITIL 2011 core books shows the processes described.

Anyone who’s managed switches over the years knows that the Spanning-tree protocol (STP) is both the best and worst thing to ever happen to the data center at layer 2 of the OSI model. On the plus side, the Spanning-tree protocol is what first allowed us to create redundant paths within our switching infrastructure, making our data center much more resilient to outages than ever before. Anyone who’s experienced a “broadcast storm” knows the full value of Spanning-tree in the traditional switching environment. We’ve also seen many improvements in Spanning-tree over the years to make it work faster and more efficiently (i.e. Rapid Spanning-tree, Bridge Assurance, and many others).

In the previous post, we discussed the need for VXLAN in the cloud along with the issues it solves. In this post, we will focus more on how VXLAN works.

In spite of an organization's best efforts to prevent downtime and avoid compromises, failures will still happen from time to time. “There are only two types of companies: those that have been hacked, and those that will be. Even that is merging into one category: those that have been hacked and will be again,” (FBI Director Robert Mueller). So what is your organization doing about it? How do you plan for failures and security breaches?

In the last two posts I discussed aspects of services in the context of some landscaping work that I’m having done. This is clearly what many people would call a “non-IT example.” I often use similar examples in my classes. However, I might initially describe an example that seems unrelated to IT, but will conclude with a challenge to students. That challenge is, “identify the IT in this example.” The truth of the matter is that most businesses these days are underpinned by some form of information technology. In fact, technology has become so ingrained into everyday services that often even the service providers themselves don’t realize how technology supports their business.