Standards Conformance

qmail is pretty strict about standards conformance. Sendmail is lousy. This can cause some problems.

The commonest problem is MTA-wannabes that only terminate lines with \n rather than \r\n. This is a clear violation of the standards.

Fortunately these mailers are being driven toward extinction by the fact that msn.com won't accept mail from them. (qmail is helping. :-) (Lest it be thought that MS are doing something entirely right there are reports that some versions of MS Outlook have this bug.)

There is a patch for qmail for anyone who has to talk to such broken mailers. I have installed it (I don't care if non-MIME non-uuencoded binary mail breaks, really!) but have not instrumented it to know if it is being used or not.

Another problem is a mailer (claimed to be sendmail, but more likely smail) that sent something like this:

To: @example.com:user@example.com

This is neither a correctly formatted route address nor a properly formatted address group, and qmail will (rightly) bounce it.

giles@nemeton.com.au