I'm having problem to connect more than one client to bitminter. I have 3 workers, that I don't want to put behind the stratum proxy - cause its bugged and it introduces one more point of failure - but looks like now I'm just able to connect with one client. are you filtering the number of connections per ip to help you to fight against the DDoS?
What happens when you try with 3 workers?
Did you report the bugs in the stratum proxy?
Currently there are DDoS attacks a couple times per day trying to break through. Normally Black Lotus is able to filter them quite effectively. Sometimes they slip through for a few minutes and lag down the server. The attackers seem to have given up pounding the server with large amounts of UDP packets and are now trying to impersonate normal miners instead. Black Lotus seems to be adapting well so far, but I'm working on my own filtering too, just in case.
If you get filtered you won't be able to make a connection to the mining server at all, you'll just see timeouts. But unless there is a big ongoing attack at the moment, you should be able to connect again in a minute or two. Timeouts have also happened for a short time when the attackers got through. In that case you would be able to connect but the request would not be serviced in time and you'd get a timeout. I'm not sure if you can see the difference in most mining clients. I have seen normal users being filtered after a service restart when everyone are reconnecting at the same time - Black Lotus has since improved their filtering heuristics to prevent this problem.
One problem is that most mining clients are badly programmed and very abusive. Retrying once per second is common, even when authentication fails. If you have 3 computers at your IP address reconnecting or retrying to same wrong name+password 3 times per second, you can imagine how that looks to a server.