On 2 Apr 2002, Gordon Messmer wrote:

Indeed, I'd say RFC 974 isn't applicable here. Note, though, that the highest-priority MX record that was returned in this particular case was a completely valid record. The misconfigured record wasn't until further down on the [prioritized] list and, in this particular case, wouldn't have been used at all. So, Courier refused to attempt delivery without even trying the highest-priority (and correctly configured) MX record, which would have succeeded and nobody would have been upset. Obviously, if the domain ever went into backup mode and starting needing the lower-priority (and misconfigured) record (e.g. the primary host was down), then I could understand the refusal to deliver, since the necessary MX record in that case would be a shanked one. Hopefully, the host admin would start noticing, but only in that case, that his backup server wasn't getting the mail and would realize he'd messed up his higher-cost (lower-priority) record. Anyway, I suppose that'd be the beginning of a different thread than my original question.

Thanks a bunch, Dan