Satellite, and ground, photos of Iran's new missile launching site demonstrates amazing similarity to North Korean facilities. Both Iran and North Korea deny that they cooperate in missile technology. But decades of North Korean missile technology, and North Koreans, showing up in Iran have made it pretty obvious what is going on.
Iran, due to lack of experience, and embargos keeping everyone else away, was forced to go to North Korea for advanced missile technology. Thus the long range (about 4,000 kilometers) Taepo Dong 2 missile that is currently built in North Korea, has a price tag on it. Iran is willing to pay well for missile technology, because North Korea also offers missiles for sale.
Iran manufactures a 1,300 kilometer range missile, the Shehab-3, as well as several others with shorter ranges. Iran has offered them for sale, but has found few prospective buyers. North Korea already has the outlaw missile market cornered. Iran has been under an arms embargo (for most major weapons exporters) since the Islamic revolution of 1979. China and North Korea have broken the embargo, but quietly.
North Korea has taken the basic Russian SCUD missile (which was developed, with the help of captured German scientists, from the German World War II V-2 ballistic missile) and improved it as the longer range (1,300 kilometers) Nodong missile. The basic SCUD design was also enhanced to produce longer range (up to 600 kilometers) SCUDs. All of these have been sold to foreign buyers like Yemen, Iran and Pakistan.