Ive been reviewing the emails blocked by our anti virus and have seen allot come from firstname.lastname@example.org (we dont have any users called this) with company.com being our domain, the emails all have the subject 'document request' and all according to our anti virus contain something (either trojan, virus, phishing etc..)
How can i prevent our domain being spoofed in this way ?
UPDATE: We are using google apps for business email. We also have an old email server from before we moved to google apps but the mx record is no longer pointed here. (its just left up as a backup copy of old emails, not sure if its even relevant but thought id mention it in case it was)