On the frontend I was already using lighttpd, but I could have used memcached on the backend that was going to be the next step if the c app didn't work. It just worked so well I didn't have to worry about it.
I'd think about switching back to a public interface that has been through these battles before. You could always keep your server up and use Nginx or HAProxy to front it for you and just pass the requests on.
Good luck with your app!
Fork Bombs are easier to pull off from the command line. Not so much with DOS. I would say that loading a large webserver for each request would use up more resources than a tiny C program. Thats the whole point of the post.
I would use Go for this service myself. Defending against abuse is hard whichever way one goes.