I have had recurring problems with a bathtub drain leaking.
After soaking the ceiling below the problem is noticed, and each time reapplying putty to the drain, seems to solve the problem.
Apparently the putty dries out in the "drain flange," but I also notice that it erodes away.
I would like to do a more permanent fix, and have considered using silicone rubber as opposed to plumber's putty.
It is hard to believe that every tub in the world needs new putty every several years to keep it from damaging the rest of the house with leakage.