Service records on former DoD civilians and military members are NOT maintained by the DoD or the services. They are maintained by NARA's National Personnel Records Center in St. Louis, Missouri. What can be released without the member's permission is:
Service Number (non-SSN only)
Highest Rank Held
Dates of Service
Awards and Decorations
Place on Entrance and Separation/Retirement
Here's a link to the appropriate page on NARA's web site:
However I think you find that we retired service members are quite willing to answer a wide range of questions from a person who it thinking about a military career.