Description:
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I have a wcf service that I am calling from php. This service is used to upload files. I am running into an issue where the request succeeds if the request is smaller than 4MB, but as soon as the request body dips above ~4MB, the soap request hangs. It eventually responds when the remote host forcibly closes the connection and I receive an error saying "Error fetching HTTP headers". I have verified that I can curl the request and build my own SOAP envelope with no problems, so I believe this problem is specific to php's soap client. I have increased my php memory_limit, default_socket_timeout, and post_max_size, with no change in results. I am able to make 4MB+ soap requests using a variety of other technologies as well, but would like to be able to do so using php's native soap client. 

Please let me know if there are any further questions I can answer to provide more information.