OSS不能通过内网上传文件

PHP SDK调用upload_file_by_file()上传文件时，
若指定oss-cn-beijing.aliyuncs-internal.com会导致上传不成功，
可改成oss-cn-beijing.aliyuncs.com就没有问题，请问怎么解决？谢谢。
Array (
    [0] => ResponseCore Object (
        [header] => Array (
            [oss-request-url] => http://mybucket.oss-cn-beijing.aliyuncs-internal.com/lz/tu.png
            [oss-redirects] => 0
            [oss-stringtosign] => PUT image/png Sun, 22 Nov 2015 09:05:20 GMT x-oss-server-side-encryption:AES256 /mybucket/lz/tu.png
            [oss-requestheaders] => Array (
                [Cache-Control] => no-cache
                [Content-Disposition] => attachment;filename=oss_download.gz
                [Content-Encoding] => utf-8
                [Content-Language] => zh-CN
                [Content-Type] => image/png
                [Date] => Sun, 22 Nov 2015 09:05:20 GMT
                [Expires] => Fri, 28 Feb 2016 05:38:42 GMT
                [Host] => mybucket.oss-cn-beijing.aliyuncs-internal.com
                [x-oss-server-side-encryption] => AES256
                [Authorization] => OSS 此处略:若干字
            )
        )
        [body] => [status] =>
    )
)