Another thing that bothers me is, that sometimes there are TCP frames with incorrect checksum. I've monitored with Ethereal and tcpdump. Both show incorrect frames, and they are always from the stunnel-end of the connection. What could be the cause of those broken frames?
I was talking to a friend of mine about these checksum errors. He had seen them also, but only if Ethereal was in the same server where the ssl software was (he had used different ssl software, not Stunnel). If he used an external pc for monitoring, then Ethereal showed no checksum errors. So it seems that for some reason Ethereal should not be run in the same server were SSL software is running. I'll test this myself, once I get a chance.
This probably answers one of my questions. The other one remains: sometimes the server doesn't respond to connections. Any ideas?
Tommi