Http headers are set by client are used to inform server about software the client is using and how the client would prefer a server send back requested information. From a servlet, HTTP request headers can be accessed by calling several methods. In your case as you just wanna know who is accessing you application, you can implement
Note: getHearderNames() method returns Enumeration
Hope this will help.
[ January 31, 2008: Message edited by: Aneel Ansari ]