I am very new to linux and need some help on iptables

I have a remote virtual privat server running fedora core 4, with root access

I want to know if I can configure iptables to do the following:

my-ip:my-port ---> iptables -> 127.0.0.1:my-port
my-ip:my-port <--- iptables <- 127.0.0.1:my-port

Please not just a YES or NO

If someone could show me how, I would be very happy

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