HTTP Basic Authentication

http://checkout.google.com/support/sell/b开发者_如何学JAVAin/answer.py?hl=en&answer=70647

Only accept messages that are authenticated by HTTP Basic Authentication, using your Merchant ID and Merchant Key as the username and password.

Any idea on how to set this up ? (HTTP Basic Authentication)

In apache you set this up using a .htaccess & .htpass files. This website will generate the files for you: http://www.htaccesstools.com/htpasswd-generator/

In IIS there is some setting under 'Directory Security' (I think) but I can't remember exactly how it works.

As for your specific google checkout problem... I'm not sure exactly what you mean, you havent provided much information...