VLAN Security Concepts

security Nov 13, 2018

A Virtual Local Area Network (VLAN) is a logical grouping of devices on one or more LANS, configured to communicate as if they were on the same segment. In order to communicate with devices in another VLAN, a Layer 3 device must be present for routing.

Private VLAN (PVLAN)

One way to simplify a multi-VLAN deployment is by use of the Private VLAN (PVLAN) feature. PVLANs achieve isolation at Layer 2 between ports in the same VLAN. This is done by designating the ports as one of three types: promiscuous, isolated, orcommunity. Each designation has its own unique set of rules which regulate the ability to communicate with other devices in the same VLAN.

Promiscuous Ports: These ports have the ability to communicate with all other ports within the PVLAN. The default gateway for the network segment would likely be a promiscuous port, since all devices need to be able to communicate with the gateway.

Isolated Ports: These ports have Layer 2 separation from all other ports...

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Route Redistribution- Part 3

ccie r/s ccnp r/s Nov 06, 2018

 

This post is the third in a series of posts on Route Redistribution. If you didn’t yet read the first two, here are the links:

So far in this series, the route redistribution examples we’ve worked through used a single router to do all of the redistribution between our autonomous systems. However, from a design perspective, we might look at that one router and realize that it's potential single point of failure.

For redundancy, let’s think about adding a second router to redistribute between a couple of autonomous systems. What we probably don’t want is for a route to be advertised from, let’s say, AS1 into AS2, and then have AS2 advertise that same route back into AS1, as shown in the figure. 

The good news is, with default settings, that probably won’t be an issue. For example, in the above graphic, router BB2 would learn two ways to get to Network A. One way would...

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Route Redistribution- Part 2

ccie r/s ccnp r/s Oct 30, 2018

In a previous post, we considered the need for route redistribution, and we also took a look at some configuration examples. This posts builds on that previous configuration and discusses how we can filter routes using route maps.

Specifically, the previous example performed mutual route redistribution between EIGRP and OSPF, where all routes were redistributed between the two autonomous systems. However, some design scenarios might want us to prevent the redistribution of every single route. One way to do that filtering is to use a route map.

For your reference, here’s the topology we’re working with:

Screen Shot 2018-09-14 at 1.14.46 PM.png

Also, with our current route redistribution configuration, the IP routing table on router R1 looks like this:

Let’s say, for some reason, we don’t want the 192.168.2.0 /24 network redistributed from EIGRP into OSPF. One way to do that filtering is to use a route map that references an access control list (ACL).

First, let’s go to router R2 and...

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Clientless SSL VPN with ASDM

cybersecurity Oct 16, 2018
 

If the security track is on your radar, particularly CCNA Security, you need to have a working understanding of configuration and troubleshooting with Cisco's Adaptive Security Device Manager (ASDM).

In this video, I'll walk through the setup of a basic clientless SSL VPN using Cisco's GUI-based ASDM software.

All the best,


Charles Judd - Instructor
CCNA R/S, BS Network Security

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Network Security Zones

security Oct 09, 2018

Our organizational IT environments are constantly changing, driven by factors such as telecommuting, cloud technologies, and BYOD (Bring Your Own Device) policies. This requires modular and dynamic architectures in place, allowing flexibility while still maintaining a rigid security posture. One of the most foundational ways to accomplish this is through the use of network security zones, which we'll take a look at in this blog post. We'll cover common security zone types, and also zone filtering policy considerations for each.

Network Security Zones

A security zone is a portion of a network that has specific security requirements set. Each zone consists of a single interface or a group of interfaces, to which a security policy is applied. These zones are typically separated using a layer 3 device such as a firewall.

In a very broad sense, a firewall is used to monitor traffic destined to and originating from a network. Traffic is either allowed or denied based on a...

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Route Redistribution - Part 1

ccie r/s ccnp r/s Sep 25, 2018

Introduction to Route Redistribution 

Until there is one routing protocol to rule them all, there is a need to have multiple routing protocols peacefully coexist on the same network. Perhaps Company A runs OSPF, and Company B runs EIGRP, and the two companies merge. Until the newly combined IT staff agrees on a standard routing protocol to use (if they ever do), routes known to OSPF need to be advertised into the portion of the network running EIGRP, and vice versa.

Such a scenario is possible thanks to route redistribution, and that’s the focus of this blog post. Other reasons you might need to perform route redistribution include: different parts of your own company’s network are under different administrative control; you want to advertise routes to your service provider via BGP; or perhaps you want to connect with the network of a business partner. Consider the following basic topology.

  

In the simple topology show above, we’re wanting OSPF and...

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Basic Security Lab

cybersecurity Aug 28, 2018
 

I get asked a lot about home lab equipment by those interested in studying cybersecurity, particularly CCNA Cyber Ops and CompTIA CySA+ students. In this new video, I'll give you a look at my setup, and give some recommendations for creating your own basic security lab and why that's important.

All the best,


Charles Judd - Instructor
CCNA R/S, BS Network Security

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Be Special

cybersecurity Aug 21, 2018

Whenever someone asks me what direction they should focus their IT career, particularly in regard to cybersecurity, my answer is always the same: “It depends.” It’s usually not a very satisfying answer, but it’s an honest one. 

Early in my own career I learned the pitfalls of not specializing in something. While there’s always a place on a support team for someone who seems to know a little bit about everything, this makes for a very poor career move. On the surface it seems like a great idea, but in reality…

 

It’s simply not possible to be an expert in everything. Everyone hits their limits with time, memory, and determination eventually, so we must choose wisely what we want to specialize in. Having no specialty is a recipe for a mediocre career, especially in cybersecurity.

So, if you’re just kicking off your security career, or re-tooling and looking for inspiration, the best place to start is finding a specialty. A few...

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Cybersecurity Jobs

security Jul 10, 2018

One question that I get asked all the time goes something like this: “How can I break into the cybersecurity field without any experience?” We hear the stats all the time about zero-percent cybersecurity unemployment and over a million job openings, but is it actually possible to get into this sector with little or no real-world exposure?

Just as with many other careers, I think cybersecurity (and IT in general, I would argue) suffers from unrealistic expectations, particularly at the entry level. I’ve had discussions with so many students who are shocked that employers aren’t beating their door down, after they’ve obtained legitimately difficult and prestigious certifications. The truth is that competition is fierce. Degrees and certifications guarantee nothing, in reality. That’s why it’s so important to be well-prepared in every possible way. 

So, the short answer is yes, it is possible to get into the cybersecurity field with...

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Video of My Cisco Live Presentation

ccie collaboration Jul 03, 2018

Last month I had the privilege of presenting a session at Cisco Live US 2018 (in Orlando Florida). If you couldn't make it to the live event, you can now check out the video of my presentation by clicking HERE.

Note that you have to login to the Cisco Live website. If you don't have an account, no worries, just click the Join Now button on that page to get your free Cisco Live account.

The presentation covers Quality of Service (QoS) toptics. However, please don't let the "CCIE" in the title make you think it's super advanced. In the presentation, we start at the very basics and build to the CCIE level.

Here's the link:  Kevin's Cisco Live Presentation

Enjoy!

Kevin Wallace, CCIEx2 (R/S and Collaboration) #7945

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