WCF call throwing a TimeoutException when client is behind Proxy - wcf

Question

I have a WCF Service which is hosted. The service calls takes anywhere between 30 secs or more than a few minutes (but less than 10) to perform its processing as per the business requirements. I am facing a problem when the client is behind the proxy and the processing on the server side is greater than 1 min. If the processing is less than 1 min, the call succeeds without any problem. This indicates that there is no issue with the connenctivity to the server through proxy. However the issue is more with timeout at the proxy server.
I get the following exception
The request channel timed out while waiting for a reply after
00:09:59.9619962.Increase the timeout value passed to the call to
Request or increase the SendTimeout value on the Binding. The time
allotted to this operation may have been a portion of a longer
timeout.
Server stack trace: at
System.ServiceModel.Channels.RequestChannel.Request(Message message,
TimeSpan timeout) at
System.ServiceModel.Dispatcher.RequestChannelBinder.Request(Message
message, TimeSpan timeout) at
System.ServiceModel.Channels.ServiceChannel.Call(String action,
Boolean oneway, ProxyOperationRuntime operation, Object[] ins,
Object[] outs, TimeSpan timeout) at
System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage
methodCall, ProxyOperationRuntime operation) at
System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage
message)
Exception rethrown at [0]: at
System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage
reqMsg, IMessage retMsg) at
System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData&
msgData, Int32 type) at
ConsoleApplication1.ServiceReference1.IMyService.GeneratePackage(Guid
clientId) at
ConsoleApplication1.ServiceReference1.MyClient.GeneratePackage(Guid
clientId) in
F:\Code\Samples\ConsoleApplication1\ConsoleApplication1\Service
References\ServiceReference1\Reference.cs:line 398 at
ConsoleApplication1.Program.Main(String[] args) in
F:\Code\Samples\ConsoleApplication1\ConsoleApplication1\Program.cs:line
26
My Configuration section looks like
<system.serviceModel>
<diagnostics>
<messageLogging logEntireMessage="true" logMalformedMessages="true"
logMessagesAtServiceLevel="true" logMessagesAtTransportLevel="true" />
</diagnostics>
<bindings>
<wsHttpBinding>
<binding name="WSHttpBinding_IMyService" closeTimeout="00:10:00"
openTimeout="00:10:00" receiveTimeout="00:10:00" sendTimeout="00:10:00"
bypassProxyOnLocal="false" transactionFlow="false" hostNameComparisonMode="StrongWildcard"
maxBufferPoolSize="524288" maxReceivedMessageSize="20000000"
messageEncoding="Text" textEncoding="utf-8" useDefaultWebProxy="true"
allowCookies="false">
<readerQuotas maxDepth="32" maxStringContentLength="200000000"
maxArrayLength="16384" maxBytesPerRead="4096" maxNameTableCharCount="16384" />
<reliableSession ordered="true" inactivityTimeout="00:10:00"
enabled="false" />
<security mode="None">
<transport clientCredentialType="Windows" proxyCredentialType="None"
realm="" />
<message clientCredentialType="Windows" negotiateServiceCredential="true"
establishSecurityContext="true" />
</security>
</binding>
</wsHttpBinding>
</bindings>
<client>
<endpoint address="http://TestServer.abc.co.za:8432/TestManager/MyService"
binding="wsHttpBinding" bindingConfiguration="WSHttpBinding_IMyService"
contract="ServiceReference1.IMyService" name="WSHttpBinding_IMyService">
<identity>
<dns value="TestServer.abc.co.za" />
</identity>
</endpoint>
</client>
</system.serviceModel>
I have tried the following options:
1) Implemented a MessageInspector and set the "Keep-Alive" to "2000000".
2) Checked the request and response through Fiddler and see HTTP/1.1 504 Connection Timed Out
My understanding is that the proxy is not waiting beyond a minute even though all the timeouts are set at the WCF service level.
How do I ensure that proxy waits till the WCF service call returns?
Would appreciate if I can get inputs to solve this problem.