It appears that during the Tehran attacks, the air defense systems did not function at all. As for Natanz, the situation is unclear. There are unconfirmed reports suggesting that air defenses may have been activated sporadically.
https://x.com/SamiraGharaei/status/1933331290717061375
several weeks ago, Israel took out the entire Syrian air defense systems, which were an integral part of the Iranian early warning system ... i also remember reading that Israel took out the primary air warning systems in Iran itself at about the same time ... The Iranians can’t see what’s hitting them or where it’s coming from ...