This is what allows you to only have one IP address from your ISP, but you can have several devices connected on your internal network in a many-to-one configuration.

You need to configure Port Address Translation (PAT).

You need a default route that tells your devices where to go.

You should configure the inside and outside interfaces.

Remember there are only four basic things you need to configure to get Internet access. The firewall setup can seem a little daunting, especially because you will most likely lose your Internet access while you're doing it.

In my case I'm using a NetGear WNDR3700, but I'll go over what you need to do at a high level, which should work with any wireless router.

I've written several posts about setting up Cisco 5510s, but this piece focuses on common things you might encounter at home like not having a static IP from your ISP or utilizing your current wireless router. I've been working on getting a Cisco ASA 5505 firewall set up at home so that eventually I can create a site-to-site VPN between my house and my office.

Cisco asa 5505 software download