SMTPServerBusy misleading error message

[dclausen]

By default, Postfix returns a 450 when the sending email address fails a DNS lookup such as the following:

#<Net::SMTPServerBusy: 450 4.1.8 <[email protected]>: Sender address rejected: Domain not found

While I agree that under normal circumstances it would be wise to stop sending should the external server actually be overloaded, in this case, none of the other emails that have been queued behind the offending email will ever be sent. As well, the error message of "server too busy, stopping delivery cycle" isn't accurate and is misleading.

Would it be possible to handle SMTPServerBusy exceptions just like Net::SMTPUnknownError, Net::SMTPSyntaxError, TimeoutError, Timeout::Error which just logs an error and continues on?