End of the road for SMTP?: I’m hearing this call more and more frequently: SMTP needs to be completely replaced.
“The protocol that has defined e-mail for more than two decades may have a fatal flaw: It trusts you. Developed when the Internet was used almost exclusively by academics, the Simple Mail Transfer Protocol, or SMTP, assumes that you are who you say you are.
SMTP makes that assumption because it doesn’t suspect that you’re sending a Trojan horse virus, that you’re making fraudulent pleas for money from the relations of deposed African dictators, or that you’re hijacking somebody else’s computer to send tens of millions of ads for herbal Viagra.”
This is a good article that looks at the issue from all sides and considers all solutions: from outright replacement, to more inventive patches.