Sender ID anti-spam technology - Is it possible to implement it in Netsuite?

I guess that there may be a number of completing anti-spam technologies doing the rounds at the moment but MS is very keen to see its sender ID technology come to the fore. See http://www.microsoft.com/mscorp/safety/technologies/senderid/default.mspx for more info. They use Sender ID in Hotmail and it is built into Exchange server, two of the most commonly used mail systems in the world.

Basically to summarise, unless I have misunderstood how this works, an email recipient (or presumably his/her ISP) looks at the mail header and determines the sender's Purported domain. The recipient then queries the mail server at that domain which will tell the recipient which IP address(s) the sender is permitted to send valid mail from. I must say that this seems to me to make a lot of sense and if it were widely implemented, it might just cut down on the spam problem.