title: When I use spring integrationi, I can't forwad a request through firewall
body: <p>Our company want build a soft gateway to controll request. and our company alreay have a hardware firewall.
  I try to use spring integration to forward a http request.
  the code is very simple,only have xml file.</p>
  
  <pre><code>&lt;int:channel id="searchRequestChannel" /&gt;
  &lt;int:channel id="searchReplyChannel" /&gt;
  &lt;int-http:inbound-gateway id="searchRequestInboundGateway"
                        supported-methods="GET"
                        request-channel="searchRequestChannel"
                        reply-channel="searchReplyChannel"
                        path="/services/outrequest"
                        reply-timeout="5000"
  /&gt;
  &lt;int-http:outbound-gateway id="searchServiceGateway"
                         http-method="GET"
                         request-channel="searchRequestChannel"
                         url="${forward.path}"
                         extract-request-payload="false"
                         expected-response-type="java.lang.String"
                         reply-timeout="5000"
                         charset="UTF-8"
   /&gt;
  </code></pre>
  
  <p>the code runs well in the other network ,but when it runs in our company's inner network,some website shows time out error. But if I vist the website directly, it runs well.
  So I want to known if the spring integration add something to my reqeust?</p>