Re:Even worse... (Score 1)

If the domain in the From address doesn't match any of the Received headers, just silently bin the thing.

The world is not that simple. You have a pacbell.net dial-up, but your e-mail is provided by your place of business-- say, UC Irvine (uci.edu). You check and send e-mail from home. Because uci.edu does not allow smtp relaying for non-authenticated smtp sessions (I'm just using them as an example, I don't really know), you have to use pacbell.net's local smtp server instead.

This means that your perfectly valid e-mail has a From address ([e-mail]) that does not match any of the servers in the Received headers (bar.pacbell.net, etc.). This is not uncommon.