I've got a pair of domains running courier-mta - one personal, and one business. Both of them show up with error conditions when the mail tools at dnsstuff.com and dnsreport.com try to verify them, with the following messages:

ERROR: I could not complete a connection to any of your mailservers!

mail.sourcelabs.com: Timed out [Last data sent: RCPT TO: ]

Can some of you try these tools on your own mailservers, and tell me if the problem is my configuration? Or are these tools just incompatible with Courier?

The issue is that there are some ISPs out there who are using these tools to determine if a domain is valid or not, and who are not sending mail to either of my domains because of these tests.