Barry: I see your “too many recipients” and raise you a “DNS failure.”

Me: You’re joking.

Barry: “Unknown address error (’550′, ['REQUESTED ACTION NOT TAKEN: DNS FAILURE'])

Me: That seems pretty self explanatory. I would close the ticket with a “not a mail issue.”

Barry: It wasn’t a ticket. It was a direct mail to me by a very well known person on the sender side. You’d die if you knew who it was. But he didn’t send me anything useful, not even an IP address.

Me: You’re kidding? Please tell me you’re kidding. Please.

This is yet another example of people bothering Barry with questions that should be answerable by anyone who holds themselves up as a delivery expert. Really.

Barry is not your free consultant. Barry has a job and it does not involve troubleshooting problems on your end. Asking questions about stupid stuff like “too many recipients this session” or “DNS failure” is why most Barry’s don’t hand out their info to senders. They don’t want to be bothered with questions just because the sender is too stupid or lazy to do their own troubleshooting.

There are two things that come to mind immediately when I see this error message and two things that I would check before even considering contacting someone.

1. This is an internal DNS failure and the MX lookup on the sender’s side failed. The sender should do a manual DNS lookup and confirm they can get a MX record (or A) record for the recipient domain.
2. This is a DNS failure on the receivers side. A little harder to troubleshoot, but some ISPs check the DNS of the sending domain before accepting mail. Make sure that the domain exists in DNS and is answering queries promptly.

Once you have checked DNS and everything is OK you can move to the next step. Open up a telnet session to the mail server and do a manual SMTP session. Use the same Mail From: and Rcpt To: that generated the 550 you’re attempting to troubleshoot. You don’t need to do the whole session, just through Mail From: and Rcpt To:.

If the Mail From and Rcpt To: addresses are accepted by the receiver mail server, then go back into your MTA and resend the message that originally failed.

It works, you’re done. If not, go back and think about what else might cause a DNS failure, then test it. Same as you did above. Repeat.

EDIT: While writing the post, I heard back from Barry. The problem was that the sending domain did not exist in DNS. This issue would have been identified at the 2nd DNS check. No mail to Barry needed.

Do they think I’m stupid? That they can just lie to me? Really! A sender contacts me and tells me that their customers only send confirmation emails and I dig through our mail from them and discover all our samples say:

NEED CASH FAST? Here you can get up to $1500 dollars cash overnight.
It’s fast and easy.

http://[REDACTED]

Get money for all your needs:
* Bills
* Special Occasions
* Cash Emergencies
* Much needed Vacation

It’s the fastest and easiest way to help pay off your bills.

http://[REDACTED]

No! you are not getting unblocked.

I pointed out to him that the sender was attempting to confirm that the recipient wanted money. My friend Barry™ took that with all the gravity with which it was intended… and then asked me if I’d been drinking at lunch.

There’s a bit of seriousness buried in his rant, though. Don’t expect to get unblocked when your mail is indistinguishable from spam. The example above was not actually the example he used, but instead one I dug out of my spam folder that was very similar to the example he did give me. I didn’t sign up for it, and I’m guessing the vast majority of his customers didn’t either. Also, what’s with calling that a confirmation? What is being confirmed?

Whoever the sender was thank you for the example of how not to ask for unblocking.

On another note: blogging will be light next week as I’m at MAAWG.

Listen to Barry.

There are also comments from various other Barrys in the comments. Those are worth reading, too.