Friday, August 12, 2016

apache 2.2 - Sender address rejected: Domain not found - after Route 53 (Amazon AWS) changes




We had been getting these messages when customers try sending us emails.




This is an automatically generated Delivery Status Notification



THIS IS A WARNING MESSAGE ONLY.



YOU DO NOT NEED TO RESEND YOUR MESSAGE.




Delivery to the following recipient has been delayed:



 sales@ital.com


Message will be retried for 2 more day(s)



Technical details of temporary failure: Google tried to deliver your
message, but it was rejected by the server for the recipient domain
ital.com by mail.ital.com. [212.212.21.212].




The error that the other server returned was: 450 4.1.8
: Sender address rejected: Domain not found




Googling this issue leads to cases which say that the problem isn't my servers problem, but it's the customers server that has trouble finding my server:



Email Bounces: Sender address rejected: Domain not found



https://www.penpublishing.com/support/emailerrors/understandingemailerrors/#spamdomainnotfound




https://stackoverflow.com/questions/14778890/sender-address-rejected-domain-not-found



The thing is That this isn't the only customer that gets this error message.



The changes we made lately with our DNS:



I have 2 hosted zones on amazon aws:



.COM domain:




Last Change - We had an MX record pointing on google emails, and we added some new outlook records (SRV, CNAME and TXT) so we can get email to outlook too.
We removed the DNSs after 2 monthes because no one likes using outlook in the office.



One before last change - We added an A record to create this sub-domain tools.example.com on Route 53, added a on my Ubuntu server. Following this: Create a sub-domain using Amazon AWS vs Creating the sub-domain from within the server - What's the difference?



.PRO domain:



One before BEFORE last change - Using S3 on Amazon AWS and Route 53, we 301 redirected the .PRO domain to the .COM domain.




In general: The .PRO has an MX record that points on the MX record in the .COM . Which always worked properly.



Following this post I created: https://stackoverflow.com/questions/32971789/how-to-redirect-an-old-domain-to-a-new-one-while-not-having-any-server-for-the




Just an A record won't cause a redirect. For that, you need a web
server in the mix. AWS has a service that can do this for you without
having to maintain and pay for such a server.



Create an empty bucket in Amazon S3, named www.example.pro and another

named example.pro. The bucket names must exactly match the domain,
with and without www.



In each bucket, under static website hosting (in bucket properties),
and choose "redirect all requests to another domain."



In the "redirect all requests to" box, put example.com. (Or
www.example.com, the same name in both, wherever you want the users to
be redirected to.




Create a hosted zone in Route 53 for example.pro.



Create two A records, one with the hostname empty, select "Yes" for
"Alias" then choose the S3 endpoint from the selection box below.



Switch your DNS nameservers with the registrar for the .pro domain to
the 4 nameservers that Route 53 assigned to the new hosted zone.



You're done.




S3 is, of course, primarily for storage... but this web site
redirection capability is a secondary feature designed for exactly
this purpose.




Can someone help me debug this problem, This is extremely urgent!


Answer



Web redirection has nothing to do with email routing, so this part you can ignore. It is 100% sure that 301 redirect has no impact on email communication. It is for HTTP protocol, http://en.wikipedia.org/wiki/HTTP_301.



The most important thing is proper DNS configuration. If you want mails addressed to yourdomain.pro domain to be accepted by yourdomain.com domain email server, you need to configure it accordingly. I think you should check your dns server for possible misconfiguration. There are many online utilities available out there to query the DNS servers and see if the received answer is correct/expected.




The error itself means, the mail server is unable to resolve the domain name of the particular sender.


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