In April 2015 the United States began prosecuting four companies and five individuals for smuggling high tech gear (mainly electronics and special power supplies) to Iran. Three of the accused men are Iranians and are part of the extensive Iranian smuggling network in the United States and other countries outside Iran. This particular operation had branches in Taiwan and Turkey. The Taiwanese connection is particularly important as East Asia has become the main source of forbidden missile and nuclear tech getting into Iran,
Because of decades of economic sanctions Iran has come to depend on China to help smuggle forbidden items into Iran. China opposes the sanctions but goes through the motions of observing them. Despite official sanction support China has always been the ultimate source of forbidden military and nuclear research items for Iran. This includes Western gear, especially stuff from the United States that the rapidly growing Chinese economy has legitimate buyers for. These American items are usually obtained by Chinese trading companies, who serve as a one-stop-shopping source for many countries. The trading companies break American laws when they ship some types of restricted (by American regulations) gear to embargoed nations. This is done using forged documents and bribes that usually mask these operations for years. These Chinese exporters have little fear of punishment at home because the Chinese government refuses to discipline its wayward firms. But these trading/smuggling companies can be hurt in other ways. That’s because U.S. regulators can reach just about every other country (even China) using the enormous U.S. presence in the international banking system. But the Chinese traders consider occasional fines and business interruption a cost-of-doing-business and passes these extra costs onto customers like Iran. Thus as the sanctions on Iran grow more formidable, prices Iran must pay go up and the Chinese profits increase even more.
This kind of smuggling employs techniques that Iran has used successfully for a long time. Many Western suppliers would simply charge a much higher price to cover the risk of being found out and prosecuted. There are, as the Iranians know well, a lot of Western suppliers who are willing to take the risk. But as the risk of getting caught, and the penalties, increase more and more Westerners gradually abandoned a lot of this lucrative business to the Chinese.
The war on Iranian arms smuggling has been intensifying since about 2004. Most countries cooperate, but not all. While Turkey has been getting cozy with Iran, the Turks still enforce international trade sanctions against Iran. But as Turkey encourages its companies to do more business with Iran, there are more opportunities to smuggle in forbidden goods that assist Iranian nuclear weapons and ballistic missile projects. Iran takes advantage of this whenever possible.
Germany was once a favorite place for Iran to buy equipment for their ballistic missile and nuclear weapons programs. No longer. For example, in 2008, a German citizen was prosecuted for running a weapons related smuggling operation. The defendant shipped 16 tons of high-grade graphite, used for making rocket nozzles, to Iran in 2005-7. The defendant mislabeled the graphite as low-grade, which was legal to sell to Iran. Another ten tons of the high-grade graphite was caught by Turkish customs officials. Germany adopted stricter export rules for Iran in 2008 and promptly began seeking out and prosecuting those who ignored the ban. More recently, Germans have been prosecuted for exporting special metals and manufacturing equipment needed for ballistic missile warheads.
Ever since the U.S. embargo was imposed in 1979 (after Iran broke diplomatic protocol by seizing the American embassy), Iran has sought, with some success, to offer big money to smugglers who can beat the embargo and get needed industrial and military equipment. This is a risky business, and American and European prisons are full of Iranians, and other nationals, who tried, and often failed, to procure forbidden goods. The smuggling operations are currently under more scrutiny, and attack, because of Iran's continuing nuclear weapons program. But the Iranians simply offer more money and more smugglers step up to keep the goodies coming.