i remember back in the old days a MX queary for a single letter between 'a' and 'm' would be sent to that root. if they wanted to, they could resolve the respo

i remember back in the old days a MX queary for a single letter between 'a' and 'm' would be sent to that root. if they wanted to, they could resolve the response. i remember having a conversation w/ paul vixie that he had either set it up (or was presenting it as a thought experiment) that he could have the email address "p@f". and i trust paul knew what he was doing with respect to DNS and RFC822 email.