On Sun, 13 Nov 2005 20:45:31 -0600, "DanG" wrote:

You must need a double wax ring on the toilet. If it were well
sealed, water shouldn't get out there. Say it another way - if
water can get out there, sewer gas can get out there. That tub
drain will be difficult to auger, it almost demands getting to the
piping. If it ends up having an old fashioned drum trap on the
line, you will be repiping it almost for certain. You might try a
plumber's friend first to see if you can jar it loose and get it
running I am having a difficult time imagining what could be
blocked enough to force water up at the wax ring and yet allow the
toilet to flow.

Collapsed pipe an/or a root-clog, further down the line,
so that there's enough volume in the pipe to take one
flush (or maybe two), but which fills up when you put
a tubfull of water into it. That will seep down over
several hours of non-use, and then appear to work again.