Just need to include the clientBaseAddress attribute with a URI in the binding tag, since the default is using port 80.
(Now change to 8001 and 8000)

< ?xml version="1.0" encoding="utf-8"?>

< configuration>

< system.serviceModel>

< bindings>

< wsDualHttpBinding>

< binding name="WSDualHttpBinding_IServerStock"

closeTimeout="00:01:00"

openTimeout="00:01:00"

receiveTimeout="00:10:00"

sendTimeout="00:01:00"

bypassProxyOnLocal="false"

transactionFlow="false"

hostNameComparisonMode="StrongWildcard"

maxBufferPoolSize="524288"

maxReceivedMessageSize="65536"

messageEncoding="Text"

textEncoding="utf-8"

useDefaultWebProxy="true"

clientBaseAddress="http://localhost:8001/WCFDuplexService">

< readerQuotas maxDepth="32"

maxStringContentLength="8192"

maxArrayLength="16384"

maxBytesPerRead="4096"

maxNameTableCharCount="16384" />

< reliableSession ordered="true"

inactivityTimeout="00:10:00" />

< security mode="Message">

< message clientCredentialType="Windows"

negotiateServiceCredential="true"

algorithmSuite="Default" />

< /security>

< /binding>

< /wsDualHttpBinding>

< /bindings>

< client>

< endpoint address="http://localhost:8000/WCFDuplexService"

binding="wsDualHttpBinding"

bindingConfiguration="WSDualHttpBinding_IServerStock"

contract="IServerStock"

name="WSDualHttpBinding_IServerStock">

< identity>

< userPrincipalName value="wandrus@mbsnav.com" />

< /identity>

< /endpoint>

< /client>

< /system.serviceModel>

< /configuration>

More Info => http://andrusdevelopment.blogspot.com/2008/03/wcf-error-http-could-not-register-url.html
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