What goods are regarded as forbidden postal items?

Guns and ammunition, alcoholic drinks, narcotics, all horticultural and agricultural goods including seeds and soil; aerial photo cameras, transmitter-receiver apparatus, pornography, most films, cassettes, CDs and videos, and any kind of fashion magazine. Of course, hunters who are traveling to Iran for hunting can get necessary permits for carrying their guns and ammunition via their travel agents beforehand.  What goods are regarded as forbidden postal items? Do I need to book my hotels before getting an Iranian visa?