spoofed email return path

[rootuser]

How do I stop email spoofing under Exim , in our server reject log showing lot of reject mails from AOL actually that site's are not residing in our server,some one changed that mail returun path to our server, How can i stop this.

[chirpy]

There is very little indeed that you can do about spoofed email headers (i.e. where you're getting the blow-back from spam or viruses) except ride them out. The best you can realistically do is to block out bounces using email filters.