URLs

Nice read about valid and invalid entry points for web applications:

• Benign Unexpected URLs – Part 1 – Missing (404 Not Found Error) Files
  http://www.clerkendweller.com/2010/10/26/Benign-Unexpected-URLs-Part-1-Missing-Files
• Benign Unexpected URLs – Part 2 – Valid Entry Points
  http://www.clerkendweller.com/2010/10/27/Benign-Unexpected-URLs-Part-2-Valid-Entry-Points
• Benign Unexpected URLs – Part 3 – Additional/Missing Parameters
  http://www.clerkendweller.com/2010/10/28/Benign-Unexpected-URLs-Part-3-AdditionalMissing-Parameters