Friend of friend says it would be great to be able to trace ip from transactions and claims to know a way to implement it.
Friend of a friend is confused. There is no IP address in the transaction. You hear about a transaction from the peers that you are connected to which may or may not be the peer that created the transaction. Furthermore even if you are lucky enough (or well connected enough) to have the person who creates the transaction as one of your connected peers, they may be running TOR which would hide their IP, or may be using a hosted wallet such as blockchain.info which would also hide their IP.
