Bitcoin is a decentralized system, so there is no reasonable place to put these IP restrictions.
If there is a single Bitcoin mining node (out of thousands[0]) that will accept your transaction, you can play.
If there is a single Bitcoin mining node (out of thousands[0]) that will accept your transaction, you can play.
Correct. There is absolutely no way whatsoever to determine the originating IP address of a bitcoin transaction, short of global network surveillance.