Note: The recommendations, opinions, and prescriptions are just one man’s view on creating a basic secure network. There are infinite ways to do this dependably, and these are the ones I think are easiest and most cost-effective.
I’m setting up my home network. I would like to allow connections with just one computer from outside the firewall, via VPN, and not allow any other incoming browser or FTP or any other sessions. What hardware can accomplish this?
First of all, it’s worth reading this explanation of home networking.
In many ways, any proper router, including an Apple Airport device, provides a firewall when you don’t open ANY holes in its network configuration. When a router or server manufacturer promotes its “firewall” as a feature, they mean that you can configure those holes more specifically.
Definition: Here, I use “holes” as English for “ports,” which on a network are numerical openings in a firewall, through which network traffic is allowed to pass. We might open those ports using a protocol called NAT (network address translation). With NAT, I can say, just for example, “When I am away from home, I want to securely access my home network with a web browser, to see my security cameras.” So I set my router to direct all traffic on port 443 (the secure web browsing port, or HTTPS) to the network address — the IP address — of my security system.
You might, for example, schedule certain ports to be open at certain times of the day, or direct certain traffic to one IP on your network, in case you did indeed want to have a web or FTP server. A firewall might also let you restrict outgoing traffic to specific ports, and will also keep a log — at a detail level you specify — of incoming and outgoing traffic.
In your case, I’m seeing that you want all holes blocked, except for those that would permit the VPN. A VPN allows you to establish a tunnel through the firewall — a tunnel that encrypts all the traffic going through it.
Can I achieve this with a VPN installed on Mac mini?
Yes, combined with a good router.
If I do not have a dedicated firewall, what is keeping the bad guys out?
See above. One of the most important strategies in security is not to turn services ON. Older Windows machines, especially before XP Service Pack 2, seemed to me to be wide freakin’ open out of the box, advertising their presence on a network and too easily offering basic file sharing, even without requiring a password. Macs are not that open straight off, but their firewall is not on by default, so whenever you turn on a service — iTunes music sharing, for example — it does not request permission to open a port, which does happen when you have the firewall on. The firewall on the Mac also includes logging.
On a laptop or other mobile device, I usually turn almost all services fully off. But It’s nice to have some services turned on on some desktop computers. It would be a shame, for example, to have music or photo sharing turned off on the machine where those things mainly reside.
So here’s the HEADLINE: To maintain good security, the most absolutely crucial technique is to lock down all services with good passwords, and use as many different passwords as you can safely store and readily access.
“Good,” in this case, means letters (some capitalized), numbers, and a special character or two. Learn where and how to change your passwords, and do so regularly. Don’t write them down. Your Mac stores passwords, certificates, and private notes in a well-encrypted file, the keychain, and that’s the best place for them. There’s also software called 1Password that’s worth a look.
Learn to manage passwords and you’ve learned to manage your security.
I am renovating my house, and I want to wire most of the rooms with Ethernet.
That is a fantastic idea, for several reasons: It increases the resale value of your house just like a good electrical or HVAC system does. It’s also important to realize that, while wireless networking is cool and all, there is nothing as reliable as a cable.
I have more information, and a table to help calculate the costs of setting up your network posted at Google Docs, right here.