I hope that somebody might help me with this.

I would like to know some iptables rule to drop all external traffic coming to port 80 in my domain (IP) using the HTTP header POST.

.. namely, droping the connection for any kind of post done by people in a specific website, and using IPtables instead of doing it with Apache.

Seems there is a "string" command in IPTables to regex this, so I think it's possible.

In summary, a translation of the following to the firewall language ...
<Limit POST>
order deny,allow
deny from all
Is this possible?

Thank you very much in advance.