[Biker_GA]

From what I've been reading, a better solution is to verify prior to accepting via SMTP, and then rejecting back to the originating server. That puts the NDR on that server, rather than your own. There have been some changes to the RFC and it's now suggested that NDRs not be sent under many conditions.

As for those bloody Microsoft pages, I'm very familiar with them. OH am I familiar with them. **banging head on desk** The email addresses dealing with SPF records are all outdated now, and I'm beginning to wonder if the pages themselves are really relevant. Once I finally get through to someone who knows what I'm talking about and get my issue resolved, I'll post the steps I had to take here.