What is the ruling on saying salaam to a person to whom you are speaking on the phone, when you do not know whether he is a Muslim or not?.
Praise be to Allaah.
The ruling is the same as when meeting him in person. If you know that he is a kaafir, then do not initiate the greeting. But if you do not know, there is nothing wrong with that.
And Allaah is the Source of strength.
Majmoo’ Fataawa wa Maqaalaat Mutanawwi’ah li’l-Shaykh Ibn Baaz, 6/286.