I hope This not same as this one http://security.stackexchange.com/questions/26198/e-mail-can-be-made-to-appear-like-it-came-from-a-big-organization I'm not asking how to protect a brands & and large organizations (Google , yahoo, etc ..), but how can a normal user protect himself . As far as i know there are worms that can get an email's address books , And there are programming libraries that enables users to craft packets . By using both (stealing the address and crafting an email packet and send it to the right server ) , a malicious hacker should be able to send the victim an email that will look like it came form one of his friends (asking for money for example ) . So beside the typical way ,that is ; calling the one that the hacker claimed to be is there a technical way to detect such fake messages ?