asp.net - WCF error over the internet only -

i have wcf problem. been stuck here days.

• i have wcf service , client working on intranet.
• i deployed same service/client on our iis server exposed on internet. service, able access workstatation, using internet site (the .com address)
• however, when accessing same .com site using computer not connected our network, it's giving me dreaded "the http request unauthorized client authentication scheme 'negotiate'. authentication header received server 'negotiate, ntlm'" when accessing service

other info: client authenticates me. when client accessing wcf service, error.

client web.config:

<system.servicemodel>   <bindings>    <basichttpbinding>     <binding name="basichttpendpoint" closetimeout="00:01:00" opentimeout="00:01:00"      receivetimeout="00:10:00" sendtimeout="00:01:00" allowcookies="true"      bypassproxyonlocal="false" hostnamecomparisonmode="strongwildcard"      maxbuffersize="65536" maxbufferpoolsize="524288" maxreceivedmessagesize="65536"      messageencoding="text" textencoding="utf-8" transfermode="buffered"      usedefaultwebproxy="true">      <readerquotas maxdepth="32" maxstringcontentlength="8192" maxarraylength="16384"       maxbytesperread="4096" maxnametablecharcount="16384" />      <security mode="transportcredentialonly">       <transport clientcredentialtype="windows" proxycredentialtype="none"        realm="" />       <message clientcredentialtype="username" algorithmsuite="default"  />      </security>     </binding>    </basichttpbinding>   </bindings>   <client>    <endpoint address="http://exposedoutside.com:80/site/myservice.svc"     binding="basichttpbinding" bindingconfiguration="basichttpendpoint"     contract="wflservicereference.iworkflow" name="basichttpendpoint" />   </client>    <behaviors>      <endpointbehaviors>        <behavior name="">          <datacontractserializer maxitemsinobjectgraph="2147483646"/>          <clientcredentials>            <windows allowedimpersonationlevel="impersonation"/>          </clientcredentials>        </behavior>      </endpointbehaviors>    </behaviors>  </system.servicemodel> 

i didn't need specify port. also, added in code-behind

dim wcfservice = new wcfserviceproxy.myserviceclient() wcfservice.clientcredentials.windows.allowedimpersonationlevel = system.security.principal.tokenimpersonationlevel.impersonation 

am missing something?

thank in advance.

can have whether can find answer thread? https://stackoverflow.com/questions/6035805/digest-authentication-with-reliable-messaging

i think similar 1 have here except fact adding client credential did not fix me.