This request can answer the question -- Is this Harvard IP address coming from an “in-library” workstation? You can use this URL request to verify that a particular IP address is registered by LTS as an in-library workstation. Registered in-library workstations are exempted from access control to restricted resources.
Syntax for a JSONP request:
Successful requests (specified IP is registered as in-library) will return a header status of "200" (OK) and content that includes the three-letter faculty code associated with the IP address. The content of the XML response looks like this:
<message>No Data for inlib. ID: 22.214.171.124</message>
Note that how the browser displays this XML response will vary depending on browser type and configuration. Some browsers will expose the 404 error directly while others may mask the error with a simple message or substitute other content, such as a search page.