Is there a limit, and if so what is it? The following page:
http://www.iis.net/configreference/system.webserver/asp/limits
explains the following:
the maxRequestEntityAllowed attribute specifies the maximum number of bytes allowed in the entity body of an ASP request. If a Content-Length header is present and specifies an amount of data greater than the value of maxRequestEntityAllowed, IIS returns an HTTP 403 error response.
I'm not sure where I would find this attribute or if there's a standard default value I can usually expect.