Last year, I introduced you to Cisco's Security Device Manager (SDM), a free Web-based utility to help manage your routers that comes preinstalled on new Cisco routers ("Learn the benefits of Cisco's Security Device Manager (SDM)"). Since then, Cisco has made a number of improvements to SDM.
One enhancement that you should know about is the Firewall Policy Wizard. You can use this wizard to create a firewall and edit access control lists (ACLs). Here's a closer look at how the Firewall Policy Wizard works.
Any router between a LAN and the Internet needs to have a firewall enabled to protect the network from malicious attacks. On a Linksys (or another less expensive or feature-rich) router, that "firewall" could be as simple as a single radial button. For example, Figure A shows how to enable the firewall on my Linksys home router.
This is pretty simple, but it doesn't offer any customization. And if you think about it, it probably doesn't make you feel too secure either.