mail server

I need to find out what mail server I have. Google says that I should just figure it out based on my ISP, but I'm at work and my job has its own network. Is there someway to just find out for certain what mail server I have?

the actual address. I tried those and some others. Is there really no way to just like send an email with that information attached or look at the program sending the email and see what mail server its using?