• Request goes through gateway-http than in response we get Content-Length and Transfer-Encoding headers. I am testing in 6.3.0 R5.

• Response via gateway.

  HTTP/1.1 200 OK
  Content-Type: text/xml; charset=UTF-8
  Accept-Encoding: gzip,deflate
  breadcrumbId: ID-cpandey-pnq-csb-34625-1515753822042-0-5
  Host: localhost:9000
  SOAPAction: http://order.camelinaction/Order
  User-Agent: Apache-HttpClient/4.1.1 (java 1.5)
  Content-Length: 171
  Server: Jetty(9.2.21.v20170120)
  Transfer-Encoding: chunked
  
  <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"><soap:Body><resultCode xmlns="http://order.camelinaction">OK</resultCode></soap:Body></soap:Envelope>
  

• Response when invoking service directly.

  HTTP/1.1 200 OK
  Content-Type: text/xml; charset=UTF-8
  Accept-Encoding: gzip,deflate
  breadcrumbId: ID-cpandey-pnq-csb-34625-1515753822042-0-9
  Host: localhost:8183
  SOAPAction: http://order.camelinaction/Order
  User-Agent: Apache-HttpClient/4.1.1 (java 1.5)
  Content-Length: 171
  Server: Jetty(9.2.21.v20170120)
  
  <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"><soap:Body><resultCode xmlns="http://order.camelinaction">OK</resultCode></soap:Body></soap:Envelope>
  

• Above it is apparent that gateway is adding "Content-Length: 171" and "Transfer-Encoding: chunked" both but as per HTTP 1.1 specs it seems only one of them should be there https://www.greenbytes.de/tech/webdav/rfc2616.html#rfc.section.4.4.

"If a Content-Length header field (Section 14.13) is present, its decimal value in OCTETs represents both the entity-length and the transfer-length. The Content-Length header field must not be sent if these two lengths are different (i.e., if a Transfer-Encoding header field is present). If a message is received with both a Transfer-Encoding header field and a Content-Length header field, the latter must be ignored."