It's a well know secret that email addresses can be spoofed. I can send email to make it appear to be from you, from a bank, or even from the government.
I could send you email that would essentially be
From: chief@10downingstreet.uk
To: <your name>
Subject: Hi, I'm bored
There are two parts to an email, the parts email servers exchange and the parts that are human readable. The parts that email servers exchange contain senders systems and IP addresses. Parts of these are stamped by routers and are therefore more reliable.
While obviously an intrusion on your person, the critical thing is that they aren't reading your email.
To really verify the security of your server, you will need to analyze the message headers (technical, usually hidden from view) to determine the sending server.
Some questions you may have:
1) Can you stop them: no.
2) How did they find you? The same way any spammer finds you. You are just one of millions of spam emails they send.
3) How do you know if its someone you know? It could be. Check the message headers to determine if it is someone from a known system.
Mike
