Woomera
In a post above someone says you can download a product that will tell you who is attempting to enter your PC (be that a server or normal PC), that product is a part of the normal full Symantic product.
Also available, from that same supplier, but only to authorized web masters, is a product that can cross reference IP addresses from almost any site, thus telling you who has posted what from where.
Recently, in the US federal court, such a product was used to prove that a certain person had posted information that was, in that country classified and, under an agreement, that person was extradited for charge in the US.
All I am saying is, take care.