Chicago Tribune: Use Linux firewall to fend off hackers

“…If you know whom you want to allow to connect to
your Web server, you can allow only those people, based on their IP
address, to connect only to that port. In this case, that would be
port 80.

IP addresses can change. Many times, when you connect to your
ISP, you get a different IP address. Schools and businesses with
high-capacity Internet connections usually have a fixed set of IP
addresses. If you know these or you know the range of them you want
to allow, you can selectively allow just those IP addresses into
your network.

Protecting your home computer has never been easier — or more
important — and the tools to do this are just clicks away. Doing
the work with Linux can be inexpensive and fun.”

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