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I've setup a PTR record for my EC2 instance following this article: https://aws.amazon.com/premiumsupport/knowledge-center/route-53-reverse-dns/. but when I test the rDNS with a tool like dig it keeps giving me the xxx.compute.amazonaws.com domain as a result. I have waited several times the refresh time and performed the steps in the article multiple times but the record does not change. I have also set the NS record for the "in-addr.arpa" hosted zone to match the NS record of my domain.

My setup is:

Hosted zone 1: "domain.com." 
Hosted zone 1 A record: name "domain.com." value "1.2.3.4"
Hosted zone 2: "3.2.1.in-addr.arpa." 
Hosted zone 2 PTR record: name "4.3.2.1.in-addr.arpa." value "domain.com"

Am I missing something here? Are there any other steps I should take or do you have any tips on how I can further debug this?

It seems like outlook.com keeps flagging my messages as spam because the rDNS is incorrect.

Any help is very much appreciated.

Arafat Nalkhande
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Sandhje Bouw
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1 Answers1

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I've setup a PTR record for my EC2 instance following this article

You can't use these instructions for IP addresses owned/controlled by AWS. The only AWS-allocated public IP addresses that are configurable with custom reverse-DNS are elastic IP addresses, and a different process applies (from the same document) --

If you are using an Elastic IP address for your server, you can configure the reverse DNS record of your Elastic IP address by submitting a Request to Remove Email Sending Limitations (root account credentials required), and you don't need to use Amazon Route 53.

The instructions you followed are for IP address space that you control, or that has been delegated to you by your ISP. They are not applicable to elastic IP addresses. You "don't need to use Route 53," in this case, would have been more correctly written here as you "can't use Route 53."

Allocate an elastic IP and map it to the server... then you can use the request form and AWS support will configure the reverse records for you.

Public IP addresses that are not EIPs are ephemeral. Once you stop the instance, the address goes back to the pool. Starting the instance again will cause it to be assigned a different public IP address. This isn't the case with EIPs, which would be more suited to a permanent fixture like an SMTP server.

Michael - sqlbot
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  • Yes I've noticed the form, but as I mentioned in the title of the question, I don't have an elastic IP. I just have an EC2 instance with its public IP of "1.2.3.4". And I would like that IP to return "domain.com" on a reverse DNS query. Is it than impossible to configure this without an elastic IP? – Sandhje Bouw Jul 18 '16 at 22:04
  • I apologize, overlooked that in the title. Public IP addresses that are not EIPs are indeed not configurable for custom reverse DNS. You'll need an elastic IP. – Michael - sqlbot Jul 18 '16 at 22:47
  • Updated the answer to match the question. – Michael - sqlbot Jul 18 '16 at 22:52