https://www.realcleardefense.com/articles/2018/06/18/iran_syria_and_israels_red_line_113543.html
The recent skirmishes between Israel and Iranian forces in Syria raise important questions about the “rules of the game,” interests, and red lines of the primary players. Israel claims there can be no arrangement in Syria that allows Iran and Hezbollah forces to remain on Syrian soil, and that includes Shiite militias. The Israelis also insist Syria cannot be a transshipment point for advanced, game-changing weapons, especially Precision Guided Munitions (PMGs) en route to Hezbollah in Lebanon. Terrorist threats on Israel’s borders will not be tolerated.
Of course, Israel realizes the important role Russia plays in Syria and the country’s significant influence with the regime of Syrian dictator Bashar al-Assad. As such, Israeli Prime Minister Benjamin Netanyahu has invested considerable time and effort to convince Russian President Vladimir Putin and his advisors that it is in Russia’s national interest to ensure that the Iranian access abides by Israel’s red lines. After the latest meetings between Israelis and Russians (held at military, executive and working levels), Russian statements suggest these efforts are beginning to bear fruit. The Russians are apparently beginning to understand that Iran’s presence in Syria is a liability – particularly if Israel continues to keep its “red lines,” including (according to foreign sources) airstrikes against Iranian assets in the heart of this important Russian sphere of influence.