question 1: Ipchains - http://www.tldp.org/HOWTO/IPCHAINS-HOWTO.html
iptables: http://www.linuxguruz.org/iptables/h...les-HOWTO.html

question 2: As far as the difference, iptables replaces ipchains in the 2.4 linux kernel. It's setup better and it has many more features.

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