You may be able to verify military service, what years they served, possibly medals earned, but anything else is covered under the Privacy Act and won't be given out.
Sorry, forgot to mention that the only place I know of that will provide any military service info is the Military Personnel Records Division in St. Louis, Mo.
Generally, ask to see their old military ID card. Even if you are retired, they still give you a (differently colored) one.
On the bottom of the page is an email address for Glenna Whitely. You could try emailing her. She and Jug Burkette are THE experts at what you are asking about.
Another way is to cold-cock them in the face. If they shrug it off and proceed to kick your a&&, they were United States military.
or
There are an incredible number of phonies.
Here's the Navy SEAL site to find out if someone claiming to be a SEAL can be verified.
Oftentimes, people pretending to be ex-military will make some sort of claim to have been in the special forces. There is a way anyone can verify if the person is telling the truth; however it can be perceived as a challenge to that person's honor. It is a little known fact that authentic members of special forces units (whatever branch of the military) commission, at their own cost, special coins carrying the logo of their unit. Authentic members carry this coin with them at all times. There is a tradition called the "coin check" whereby you can demand that the person claiming special forces status produce the coin. If they are legit, they will dig it out of their pocket and slap it down in front of you, after which you are obliged to buy them a drink. If they fail to produce the coin, they are phonies and should be shamed out of the house. Hope this helps.
Yes ask for a certified copy of their DD214
If you are a veteran yourself and can talk to the person, it usually takes about 4 minutes to figure it out. Dates are all wrong, locations don't match up, can't tell you what their MOS was, and most importantly often fake being traumatized by whatever war they were in. Most incredible one happened to me about two weeks ago. Guy told me he was a Vietnam veteran and had some very elaborate stories. Later in the conversation he told me he was 41. Not only a liar, but apparently a mental defective.
You might try the book How to Locate Anyone Who Is or Has Been in the Military, by Richard S. Johnson
AF form 800 Request and Authorization for Permanent Change of Station - Military (to your last military base where you become seperated)
DD form 256: Honorable Discharge certificate
Personnel records history - I kept mine:):)
Ask them to give you their Serial. Any veteran will be able to rattle it off in about 3 seconds. Don't know why but its stuck in my head forever.
Get another (known valid) vet, preferably of the same service, to talk to him for about five minutes.
I have a friend who I've known on the net for years, but only just met last year- I was passing through town and stayed at his place for a few days. He took me to meet another former Marine (with the same MOS as I) that he knew in town. I didn't but just occur to me that my bona fides were being checked, it seemed like an odd detour at the time.
Fine with me- I passed with flying colors. The 'bona fide checker' knew my old Senior Drill Instructor. LOL! Small world, er Corps.
There are military web sites that allow you to enter a person's name and his rank will appear if he served.
You might try military.com