HttpClient gives Negotiate error with NTLM auth provider

Question

I am "forcing" the httpclient to do ntlm authentication by using:

    PoolingHttpClientConnectionManager connPool  connPool = new PoolingHttpClientConnectionManager();

    Lookup<AuthSchemeProvider> authProviders = RegistryBuilder.<AuthSchemeProvider>create()
            .register(AuthSchemes.NTLM, new NTLMSchemeFactory())                
            .build();

    CloseableHttpClient httpClient = HttpClients.custom().setConnectionManager(connPool).setDefaultAuthSchemeRegistry(authProviders).build();

But, when authenticating to the server, I get an annoying log message "Authentication scheme Negotiate not supported".

How can I get rid of this message?

(This will be running on a linux box, so HttpClient 4.4 JNA support for native authentication won't help.)

Answer 1

I think it is all very simple. Effectively the client is only willing to do NTLM while the server is only willing to do Negotiate, thus failing to agree on a common authentication scheme.

This is how one can adjust auth scheme preference to force HttpClient to choose NTLM over SPNEGO / Kerberos

RequestConfig config = RequestConfig.custom()
        .setTargetPreferredAuthSchemes(Arrays.asList(AuthSchemes.NTLM, AuthSchemes.KERBEROS, AuthSchemes.SPNEGO))
        .build();
CloseableHttpClient client = HttpClients.custom()
        .setDefaultRequestConfig(config)
        .build();