When I enable IIS NT Authentication I am setting : //client is XFire Client client.setProperty(Channel.USERNAME, "username"); client.setProperty(Channel.PASSWORD, "mypass"); This works for IIS Basic Authentication, but when I try NT Authentication I use the same method as above, but also add the domain name: //client is XFire Client client.setProperty(Channel.USERNAME, "mydomain\username"); client.setProperty(Channel.PASSWORD, "mypass"); On both cases, using this method to set the Username/Password sets the State object in CommonsHttpMessageSender.state object, but not in the CommonsHttpMessageSender.client.state object. NTLM Authentication appears to fail because of this. When testing a web service call by using HttpClient directly, NTLM works fine as the state object is correct. Maybe I am doing something wrong? I have had to get round this by overriding