What is the difference between an ‘A’ record and an ‘MX record’?

Since there is no standardized manual for interviewing a technical support engineer, you're likely to get a wide variety of questions depending on who is interviewing you. Some of these will be straightforward and relevant to the work you do. Others may be more obscure. Sometimes interviewers like to see if they can trip you up and get you off balance. If you're asked something you are unfamiliar with, acknowledge this, and then describe to the interviewer how you would go about locating the information.