Where did people get this idea from the Russia and Iran are allies? Russia only supports Iran insofar as they might create an obstacle for the United States. That obstacle is working and will continue working due to Trump's intransigency. They're not natural allies because both of them have a natural competing interest in the Caucuses.

Israel and Russia *are* in the position to be natural allies because both compete with Turkey and don't really overlap with each other's interests. Notice that Israel is not on Russia's "Unfriendly Countries" list. Israel also has a *lot* more cultural overlap with Russia than it does with any European country or the United States.

The key factor here is that countries are effectively withheld from their "natural" allegiances because of the influence of US foreign policy which simultaneously wanted a free Europe under their economic umbrella, and a subjugated Arab world under Israeli might; Israel keeps its neighbours either too weak to oppose US interests (Syria, Lebanon) or too frightened (the Gulf, Jordan, Egypt). If the US didn't provide money to support this contradictory setup then Israel and Russia would be open allies and Iran would be sidelined.

Russia wants Iran to be roughly the same thing as the US wants Ukraine to be: a thorn. Strong enough that they don't roll over into their opponent's court, but not strong enough to definitively assert their independence and sovereignty. For a thorn that doesn't at least invite the possibility of attack is a pretty bad tool at pricking their adversary. If US influence in Israel were to weaken, we'd see Russia attacking Iran alongside them.