The domain is reported to be bad via DNS

[HCHTech]

Over a year ago now, I migrated a client from an onsite Exchange server to MS Hosted Exchange. The migration went fine. We did it over a weekend and by Monday morning email was flowing normally.

This client has about 35 employees and 1,000 customers. All employees send and receive email all day, every day. My point is, it's working.

They are having trouble receiving messages from an large, DC-based industry organization. This organization has listservs, they do conference registration, webinars, etc., as well as send and receive individual emails. Intermittently, but regularly, emails do not get delivered to my client. The organization either reports that they do not receive a bounce at all, or they get the above message about DNS. Individuals have reported that they get a bounce with the "no such address" message, when replying to an email they received from my client! Other times, the email goes through just fine.

I have checked and rechecked the settings. I have run the MXToolbox tests which were unremarkable. Emails do not end up in the junk folder in Outlook. They are not in the mailbox when using web access. Either the mails just vanish into the ether and never get delivered, or they are bounced from some DNS server, or maddeningly, they are delivered just fine. No other customer or individual has reported any trouble sending email to my client.

I suspect [that one of] the organization's onsite exchange server(s) have a bad/corrupted DNS entry from before my client went to hosted exchange. But I cannot prove it. Of course, they are pointing the finger back at my client, who, you guessed it, is telling me to fix it.

I'd appreciate some suggestions on what to do next.

 

[nlinecomputers]

Can't argue with stupid. If only one email server has problems then it must be a problem with that server.

 

[Markverhyden]

^^^ What he said. I'd tell your customer that you need to get some of those emails forwarded to you, including full headers to review. We all know "reports" by EU's are always incomplete and misleading. I just got a phone call from a customer, a church. She said she had a phone call from the President of the Bank they use saying he got an email from her telling him to transfer all of the money from the Church account to her personal account. I told her to have him forward that email to me. There are so many that this could have happened.

 

[ComputerRepairTech]

Individuals have reported that they get a bounce with the "no such address" message, when replying to an email they received from my client! Other times, the email goes through just fine.


I suspect [that one of] the organization's onsite exchange server(s) have a bad/corrupted DNS entry from before my client went to hosted exchange. But I cannot prove it.

Wouldnt the "no such address" bounce message be coming from the wrong server in the mail headers?

 

[HCHTech]

Wouldnt the "no such address" bounce message be coming from the wrong server in the mail headers?

You would think. I've requested bounce messages be forwarded to me - we'll see what they say. This is a fairly big organization, I think they are just too lazy to look at the problem. I was speaking to someone I know who is on the BOD of the organization - he said they spent >$1M on computer equipment in the last year to upgrade and prepare for growth. I guess it didn't go well, the CIO lost his job over it.

The problem with my customer has been happening for a while, but because it was intermittent, I guess they were just living with it. I hope the headers are instructive. I would love to point out one of their own servers as the problem with proof in hand. I read that it's possible to override TTL values to as long as 68 years (!). I wonder if there is a DNS cache that is corrupted somewhere. I wonder if I can setup some logging to see if the mail from the organization is trying to come to the address of their old exchange server...

 

[YeOldeStonecat]

All just a guessing game until you see the headers from the NDRs...until then...you're just volunteering time thinking about it and guessing.

 

[HCHTech]

Huzzah - it's fixed. The problem was on their end, as suspected. Something about the cache on their Exchange server(s) not updating correctly when we moved from local to hosted exchange. I found a KB article about it, which set them on the right road to a fix, apparently.

 

[nlinecomputers]

Ok so the organization whose email was bouncing is ALSO migrating to Office365? The KB you posted would apply to them not you or is your client still running an exchange server as well as the O365?

 

[HCHTech]

We are using hosted Exchange only. The organization is using some combination of local and hosted servers. Beats the hell out of me, I've never seen the joint. We had a conference call with them this morning and they just said the KB helped them flush out the issue. I'm just glad it's fixed.