Recent posts

EIGRP Route Advertising

May 15, 2010 | 2 minute read

In the forums that I frequently visit I always see people asking how EIGRP route advertising works. The users are not sure how to correctly use the “network” command and usually use more commands than are necessary. So in today’s post, using the diagram below, I will explain how to advertise EIGRP routes properly. Now before we get started let ...

Get Involved - Forums

April 18, 2010 | 2 minute read

Whether you are are a seasoned Cisco professional or just starting out, one of the best sources of information you will find (apart from this blog :P) are internet forums. You will be amazed at just how much you can learn from them, and, if you have the time, how much you can teach others too. It is also a great place to “network” (excuse the pu...

CBAC in Action, Part 2

April 18, 2010 | 1 minute read

In my previous CBAC post I covered how to deny all external traffic unless it is in response to a request someone on the LAN has made, e.g If you send a ping, CBAC will allow the ping reply traffic to come through the firewall. However, this situation may not be ideal for everyone. What if you wanted to allow one or more protocols in to your ne...

CBAC in Action, Part 1

April 18, 2010 | 3 minute read

In a previous post I talked about CBAC and a few of the ways in which it, in conjunction with NBAR can be used to secure your network. Today I will create a lab to show you how to put it to good use. In this lab we have four routers, R1, R2, R3 and R4 (very original I know). Here are there designations: R1 = Local LAN - Your network R2 = ...

CBAC Firewall

April 17, 2010 | 1 minute read

In my previous post I mentioned the Cisco IOS firewall feature known as CBAC (Context-Based Access Control). Today I will describe it in more detail and explain how you can use it to increase the security of your network. As you may know, a firewall is used to protect your network from the outside world and all of the nasty hackers out there. W...