Tag: cisco

Cisco stuff

Using MAC Access-lists

We ran into this today, and, though I knew it existed, I never actually saw it in the wild.  I’m talking about MAC access-lists. In the example setup, we have a DMZ off of a firewall that contains a whole…

Free and Awesome Network Tools

We all have limited budgets these days. Long gone are the days of unlimited resources and uncontrollable expansion of the network, so it’s important that any network dude or dudette pay attention to the open-source world. Below is a list…

Dynamips and Dynagen

I’ve run across articles for these apps a thousand times, so I thought I’d get in on the action. Dynamips and dynagen are a pair of apps that make simulating Cisco routers very easy. I use them constantly at the…

Object Tracking and HSRP

We’ve done some tracking with HSRP in other articles, but there are lots and lots of ways to use object tracking on an HSRP device. In our example network, we tracked the interface, and, if it went down, we decremented…

Intro to Policy Routing

I like [tag]layer-3[/tag] [tag]switch[/tag]es. They give some great flexibility and bang-for-the buck, but most people overlook one issue with these things that can cause security problems. Most people configure the [tag]VLAN[/tag]s, put an IP on the VLAN interfaces, and put…