In early June Sudan announced that it would not follow through on its 2012 plan to obtain an air defense system from Iran. This planned purchase was in response to a late 2012 air raid (allegedly by Israel) that set fire to an ammunition factory built with Iranian assistance. Israeli aircraft have attacked Sudan several times in the past few years, mainly to halt the movement of Iranian weapons (especially long range rockets) to terrorists in Gaza and the Islamic terrorists based in the adjacent Egyptian Sinai Peninsula.
It was never clear what air defense weapons Iran would provide. Iran itself has been trying (without success because of interference from Israel, the U.S. and UN embargoes) to obtain S-300 anti-aircraft systems from Russia and the similar HQ-9 system from China. Iran says it has developed its own modern air defense systems but there is little evidence of that. That may be the main reason behind the Sudanese move. Officially Sudan explained that it was withdrawing its request for an Iranian system because it did not want to upset fellow Arab nations. Saudi Arabia is leading a coalition of Arab states to block Iranian efforts to control Arabia (and Arabian oil and religious shrines).
Sudan’s leader (president Omar al Bashir) has other reasons to maintain good relations with the Arab states. The UN has indicted Bashir for war crimes while fighting various Sudanese rebel groups for over a decade. Bashir has used tactics like turning loose slavers, chasing entire tribes from their traditional lands and killing lots of civilians. Bashir needs help from the Arab states to keep the UN from grabbing him for trial.
Meanwhile Iran continues to provide Sudan with weapons and, more importantly, with building ammunition and weapons manufacturing plants. It was one of those Iranian built plants that got burned down in 2012. Sudan admits that it gets help from Iran in building these factories but denies that it helps smuggle Iranian weapons to Islamic terrorists in Egypt and Gaza. But Egyptians, as well as Israel and many Sudanese know that this smuggling does take place and Israel does not deny that it might be responsible for the occasional air attacks on weapons just arrived from Iran or truck convoys carrying them north into Egypt.