Spam to someone else's domain name

[#1]

I'm getting mail (marked spam) to addresses such as:
kkincaid@unity.ncsu.edu
Clearly nothing to do with my address.
How do they get to my inbox.

[#2]

probably what is called back scatter, you would have to look at the source, it probably has your address as envelope to, mind you as spam, dont open it normally, depending on your reader how you look at the source

[#3]

Thanks PP.
I just had a look at properties and it is as you said.

[#4]

Do you have Catch All switched on?
If it is no inconvenience to you, it might be an idea to go into the member centre e-mail settings and switch it off.
This way you should only get mail addressed to the main box plus aliases.

[#5]

Do what I did.
I set up a new email address and made that the catch all.
I only access it via webmail so any spam etc. stays there but I can check to see if any proper mail has found it's way there.

[#6]

Thanks for the advice.
Yes I do have catchall on.
I'm not really bothered by the spams, I only get a few (I set message rules in OE)
I merely wondered how they were getting here.
Many thanks again.