>Speaking of validation, there is one interoperability issue the draft >doesn't mention: Mail address verification by SMTP callout. For >verification of envelope senders this works fine, but there are other >applications where a mail address needs to be verified:
It's certainly an issue. I thought I mentioned it. As you've observed, some systems attempt to verify a 2822 address by doing a fake bounce with a null sender, which BATV doesn't like. There's a few MTAs which do this as a rather lame anti-spam technique, notably a plugin to EXIM. >I noticed that a few details are missing or at least rather vague. OTOH, >maybe they don't need to be specified. The only scheme currently defined >is prvs, which can only be validated by the original sender. Right. R's, John
