The "dba" is a trade name, not a trade mark...this often an important, but sometimes confusing, distinction. Under Georgia law, those who use a trade name are required to register it in the county in which the business is located. Based on your example, it appears John Doe LLC is using the trade name, and as such, it should be registered. Registration is done via the Superior Court Clerk and there is a publication requirement (the clerk's office can tell you the specifics, and most can provide the registration form).
The law also provides that using a trade name without registering it is a criminal offense, albeit a misdemeanor; however, I suspect few, if any, have ever been prosecuted for violating this statute.
[This communication is intended as general information and not specific legal advice, and this communication does not create an attorney-client relationship.]
Yes. If you use a dba you need to register it under most state laws. See a local business or IP attorney.
I am not your lawyer and you are not my client. Free advice here is without recourse and any reliance thereupon is at your sole risk. This is done without compensation as a free public service. I am licensed in IL, MO, TX and I am a Reg. Pat. Atty. so advice in any other jurisdiction is strictly general advice and should be confirmed with an attorney licensed in that jurisdiction.
Yes. Speak with a Georgia-licensed trademark attorney to assist with the process.
The above response is general information ONLY and is not legal advice, does not form an attorney-client relationship, and should NOT be relied upon to take or refrain from taking any action. I am not your attorney. You should seek the advice of competent counsel before taking any action related to your inquiry.