Sings of drafting problems? What do you say? Comments please.
(Photo #1 Stains exiting the drain valve)
(Photo #2 Signs of leak or corrosion)
(Photo #3 Spent matches on the floor, re lighting issue)
First thing I would do after seeing something like that is to go outside and see if there is a storm collar and rain cap on the exhaust. Also make sure that the vent is not obstructed or in an inappropriate location.
Looks like water staining and drafting.