What does X-Backside-Transport Header do?

Question

I have come across this header for the first time and not sure what it does or mean. I have searched around and couldn't find what I was looking for.

I am trying to consume a SOAP API using PHP SoapClient class and it's returning an empty response and these response headers. Also, no exception is thrown.

HTTP/1.1 200 OK
X-Backside-Transport: FAIL FAIL,FAIL FAIL
Connection: close
Transfer-Encoding: chunked
Content-Type: text/xml
Date: Tue, 21 Jun 2016 20:09:50 GMT
X-Client-IP: xx.xxx.xxx.xxx

Any help is appreciated.

Answer 1

It seems that the web service you're trying to communicate is behind the xml firewall (probably IBM DataPower, it does send X-Backside-Transport header on failere) and blocks the error response (aka. fault message). This is the default behaviour for the xml firewalls. Root cause can be malformed soap message (i.e.: wrong data type) or an server site exception.

In order to solve the problem, you should contact with the web service owner.