In the following image, you'll see a network topology.  In this topology, the routers are running the RIP routing protocol.  As is tradi...

One of the big topics currently in Cisco's security track is Netflow.  According to Cisco, "NetFlow provides valuable information a...

A well known problem for network and security professionals in the enterprise is asymmetric routing.  At it's simplest, this is where tr...

To alleviate the fear of overburdening the CPU due to the collection of NetFlow statistics, Cisco gives us the option of using Sampled NetFl...

One of the most commonly covered security features when it comes to Cisco security is the ZBF.  It wouldn't be much of a network securit...

Have you ever wanted to create an ACL by country?  There's a number of different ways you can go about it.  Certain models of firewalls ...

Here's a quick post on a very useful command when working with ACLs.  I first heard about it while watching a CBT Nugget video, and I ca...

In a nutshell, reflexive ACLs allow packets to be evaluated based on upper layer session information. You use reflexive ACLs in order to per...

There is one more feature of the Cisco access servers that I do not see mentioned very often. Maybe it's been talked to death and I jus...

Racked up in my lab, I have more routers, switches, firewalls and access points than I care to count.  These devices are all in the basement...

The different types of ACLs are first identified by the line number used. Standard IP ACLs use numbers in the range of 1 – 99 and 1300 – 199...