Internet Marketing Fast Facts, Last Updated:09/07/2010 Spammers frequently seek out and make use of vulnerablethird-party systems such as open mail relays and open proxy servers. TheSMTP system, used to sendemail across the Internet, forwards mail from one server toanother; mail servers that ISPs run commonly require some form ofauthentication that the user is a customer ofthat ISP. Open relays, however, do not properly check who is usingthe mail server and pass all mail to the destination address,making it quite a bit harder to track down spammers. |