According to a warning issued by U.S. CERT, a configuration problem with your DNS servers could expose detailed information about your DNS zones. Even though this has been a known issue for a decade and a half, there are still many servers that are operating in a vulnerable state.
About The Author
Debra Littlejohn Shinder is a technology and security analyst and author specializing in identity, security and cybercrime, utilizing her past experience as a police officer and police academy/criminal justice instructor. She has written numerous books and articles for web and print publications and has been awarded the Microsoft MVP designation for fourteen years in a row.