Helping people with computers... one answer at a time.
Among the spam we all get are messages that we appear to have sent ourselves. From-spoofing is just a way spammers try to get their email delivered.
I get email from:
where "email@example.com" is someone I don't know, but "firstname.lastname@example.org" is, in fact, my email address. It as if the email was sent by me, but I did not send it.
How do I stop these email from coming into my box? It's usually for drugs or financial services that I don't need or would never be interested in. How can they use my own email? I can't block them as it says it is illegal to block my own email.
I'll start with the bad news: there's almost nothing you can do.
This is spam, pure and simple. Abusing your email address is only one of many techniques spammers use to throw their garbage into our mail boxes.
The remedies are pretty standard, albeit less than 100% effective.
What you're seeing is called "spoofing" or more correctly "From-spoofing" - sending email that appears as if it's coming "From:" someone that its not.
Spoofing is a technique that is used in just about every bit of spam you see today. Spammers are trying to hide where the email comes from and are doing so very effectively. The From: address is meaningless on spam - it tells you absolutely nothing. It requires more detailed analysis of the email headers, and even then at best you might be able to get the IP address of the computer sending the email. As I've discussed ad nauseam, the IP address is pretty much useless to you and me.
The fact that you're seeing your email address used in the "From:" field shouldn't alarm you. It might be annoying, but there's no need to worry about it. You're already on spammers lists to get spam and they're using that same list, or variations of it, to select which addresses to use when spoofing. And there's currently no effective way to stop them from spoofing.
When you see your own address spoofed in the From: field of spam, it's happening for one of two reasons:
They're trying to spam you, and know that it's unlikely you'll block email from yourself. In fact, as you've seen, it's not even always possible, but I'd consider it a bad idea even if you could do it. It'll prevent certain types of legitimate email from reaching you.
They're trying to spam someone else, and what you're seeing is a bounce message indicating that the original spam was rejected by its intended recipient. Since the email looks like it came "From:" you, you get the bounce message.
Now, as to why the "email@example.com <firstname.lastname@example.org>" where the two email addresses don't match, or the more common "Name <email@example.com>" where the name is obviously unrelated to the email address, I can only speculate. My guess is that it's either intentional confusion to perhaps boost the chance that recipients will open the email, or a side effect of the tools that spammers use that may not be able to put together a proper name/email address pair.
"But what do I do?"
First, realize there's nothing you can do to prevent From-spoofing. Eventually your email address is going to show up in the "From:" field of spam that you had nothing to do with. In fact as you've seen, it probably already has.
The only thing you can do is to keep doing whatever it is you do to control spam. I run two levels of spam filters, and even then some gets through. It's a juggling act because I don't want to risk marking something as spam that isn't - hence a little more spam gets through. Depending on your mail program and your mail provider, you may have similar or additional options available.