Configuration Http Proxies in WCF
When using Http, proxy configuration madness is a fact of life. If misconfigured, you can wind up trying to decipher obtuse 502 (Bad Gateway) and 504 (Gateway Timeout) errors.
Fortunately there are a number of binding settings available in WCF to control your Http proxy usage. These settings are available directly on BasicHttpBinding and WsHttpBinding (as well as on HttpTransportBindingElement when you are using a CustomBinding).
public boolUseDefaultWebProxy(default == true): if set to true, will use the global value HttpWebRequest.DefaultProxy as your proxy. HttpWebRequest.DefaultProxy is controllable through System.Net config, and defaults to using the system proxy settings (i.e. when you see in your Internet Explorer properties).publicUriProxyAddress(default == null): If you want to specify a proxy directly you can set a proxy Uri directly here. To ensure no proxy is used you can specify “null†here. In both cases be sure to set UseDefaultWebProxy = false as well.public boolBypassProxyOnLocal(default == false): used in conjunction with ProxyAddress for when you specify a proxy. If you want “local” addresses (i.e. addresses on your intranet) to connect directly without using the proxy, set this value totrue.publicHttpProxyCredentialType HttpTransportSecurity.ProxyCredentialType(default == None): Specifies the authentication mode used with your Http proxy. For custom bindings the equivalent setting ispublicAuthenticationSchemesProxyAuthenticationScheme(default == Anonymous) onHttpTransportBindingElement. For proxy authentication we will obtain the credential using the shared WCF provisioning framework (SecurityTokenProvider, etc). We simply pass in the proxy address (rather than the target address) for acquiring these credentials.
One last note about proxies: if you see a 502 or a 504 error returned to your client, then your client is using a proxy server. If this was not your intention, you can disable the server by setting UseDefaultWebProxy to false, and using the default ProxyAddress of null. The other possibility is that your proxy is misconfigured and you can use the above settings to rectify that situation 
April 21st, 2006 at 8:03 am
I was playing with these settings a while back, trying to get a proxy-based trace utility to work, and in every case it seemed to ignore my new settings. Any ideas?
April 21st, 2006 at 11:09 am
Hmm, we’ve verified these settings in many different configurations. I’ll take a look at your code.
July 22nd, 2006 at 9:28 pm
I am having the same issue. It ignores proxy settings and connects without the proxy.
Here is my client configuration:
July 23rd, 2006 at 10:10 pm
I’d need to see you configuration (it seems to have gotten stripped in the comment) to know for sure. If you have the default settings then you will use what’s in IE. Otherwise you need to remember to set defaultWebProxy=false as well as setting proxyAddress=”http://myProxy” from within your config on the basicHttpBinding or wsHttpBinding.
September 27th, 2006 at 8:10 pm
[…] In my earlier post on HTTP proxies I noted that all of our transport security implementations (including HTTP proxy authentication) leverage the shared WCF-wide credential provisioning framework. As a result, it’s pretty straightforward to configure your proxy credentials. I think what trips people up is that we don’t have a separate “ProxyCredentials” object. Rather, both the proxy authentication and the ultimate server authentication access credentials from the same location (such as ChannelFactory.Credentials). […]
April 7th, 2008 at 4:36 am
I’m new to WCF and am trying to get a handle on LINQ via the walkthrough in MSDN which connects to http://terraserver.microsoft.com/TerraService2.asmx. However I am behind a corporate ISA firewall/proxy that requires authentication. I can surf the web with IE just fine so my default proxy settings are OK. but the following app.config settings still fail with: (407) Proxy Authentication Required ( The ISA Server requires authorization to fulfill the request. Access to the Web Proxy filter is denied). The settings are the auto-generated ones with proxyCredentialType=”Windows”. I also added the impersonate bit just in case - not sure if it’s relevant though.
I assume I am not setting the proxy credentials correctly and would appreciate any pointers on how to do this…
May 3rd, 2008 at 11:16 am
If your IE settings are correct for hitting the terra server, then you shouldn’t need any specific WCF proxy settings. The default of “UseDefaultWebProxy = true” will simply use the settings from IE by default