Gentlemen, I decided then to get acquainted with centos, actually need to configure iptables, it's all just principle, and on other systems does not cause problems, but then came to a screeching halt. opened documentation
wiki.centos.org/HowTos/Network/IPTablesin fact all is clear, create the script, write the rule from the example, the result is:
./firewall.sh: line 7: iptables: command not found
and so all commands that are not so can not understand
centos 5.5 final