Some ideas (Score 1)

There are many people thinking how to block o avoid to receive spam ... I'm using a antivirus/antispam solution in-a-box called Astaro Security Linux (ASL - www.astaro.com) This solution has a good verification system that everyone should improve ... When an email arrives to the ASL, it can make a lookup for the domain name ... is the domain name exists, it can ask to the domain for the mailbox existence .. However, this technology needs the null-address capabilities turned on in the sender's domain .. It's a good idea too .. ---- I think that SPF and SID are good technologies too ... Another one solution could be the a small dialog between the sender and the destination email server .. When an email arrives to the destination email server, it's send a confirmation message, so, the sender must confirm this message ... The problem here, is the bandwith wasted and the increment of hardware resources uses ... ----- See ya in the Cyberspace ...