Presently if a request is made to the application for domain that the preside site doesn't know how to process or to an IP it will throw a 500 error.
I think that this is something that can be reasonably predicted and as such we should handle with a 404 that the resource cannot be located or processed and not found. Assuming that the act of raising a 500 carries with it more consequences on resources and or unnecessarily filling log files for actual errors.
Especially given that there is no easy way of suppressing the error e.g. to an unhandled IP rather than >dev>null within the nginx or webserver config