Unable to access any web services in the _vti_bin folder from SharePoint web server

We have an internal portal hosted on a SharePoint web server. There is a separate server for indexing the portal content. I have a custom web application that invokes the SharePoint search web service and it works fine on my development machine. However when I deploy it to the SharePoint web server, I get this message

"The request failed with HTTP status 401: Unauthorized."

If I try to access the web service from the browser (http:///_vti_bin/search.asmx) from the production serv开发者_StackOverflower, I get the 401 page. But it works fine from the any other machine. This is an internal portal. Any help would be deeply appreciated.

Thank you.

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If you get the 401 error when browsing any Sharepoint page from the local machine, try checking out this article or this article (both from support.microsoft.com)

It describes how to disable/work around the loopback check introduced in windows 2003 sp1.