Iran stands today isolated like no nation before, at least since electronic banking became the standard. They have been cut off from Swift, the Society for Worldwide Interbank Financial Telecommunication, so money can’t enter or leave the nation except that which is carried over the border manually. This came in response to their failure to allow an inspection of their nuclear program.
How Iran came to be contained so tightly and so quickly may set a new precedent for dealing with rogue nations. But the process for doing this is not what most people would ever expect.