So far, we have talked about the most widely used function of Iptables: Packet filtering, and a bit about connection tracking and logging. Leaves us with one more function: rate limiting.
Rate limiting can be a life saver: It can limit the packages coming into the PC or network and this way spare your services from a DOS syn-flood attack.
Now the technical stuff: How to fill your table with rules.
First of all, you need a 2.4 kernel and netfilter support. Next you should off course install iptables itself, and load the module into kernelspace. If it isn’t already compiled in to the kernel it self, you can load in with “modprobe IP_tables”
Nowadays a lot of people have a broadband internet connection, and when you are using more than one computer then an internet broadband router is the easiest way to go.
Easy to configure, and really secure… The only thing is, that it often isn’t scalable enough if you are running a lot of services in your network, and you like to keep it all secure.
Firewalls are one of the symbols of security. If you say firewall, everyone knows you are talking about security. Although firewalls are indeed a good method to secure your network, you should be aware they can be a pain in the ass.
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