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Right now our domain name and DNS are still hosted by our old provider until we make the full switch to Amazon AWS.

We run a lot of subdomains i.e. vendor.mydomain.com which were previously setup as websites on our old host. I deleted the subdomain on the oldhost and replaced it with a cname on the mydomain.com level for vendor to point to AWS, all is working well.

Now I need to add some TXT records for mailgun to verify my domain and I'm not sure where / how to do it. Mailgun is looking for and expecting a CNAME record email.vendor.mydomain.com. I tried creating this on mydomain.com as I did for the vendor CNAME, it lets me create it but it never seems to be detected by mailgun.

I figure I could go with the configuration where I create a subdomain on my original host, but then the nameserver of my old host takes over for vendor.mydomain.com. In this scenario I'm all good with the Mailgun CNAME's etc, but I don't know how to effectively point to AWS for vendor.mydomain.com as the CNAME on the domain level no longer works.

Thoughts / suggestions welcome!

Tom
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1 Answers1

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If, on the authoritative server for example.com, you have a CNAME record for subdomain.example.com, no other records on that same server can be valid for, or under, that subdomain, because the CNAME effectively blocks everything at or below itself by saying "stop, look elsewhere... specifically, look here."

Create a hosted zone in Route 53 for example.com. Note the 4 awsdns name servers it assigns to the hosted zone.

For each subdomain you need on Amazon, create 4 NS records for each subdomain on the example.com authoritative servers.

vendor NS ns-xxxx.awsdns-yy.com. vendor NS ns-xxxx.awsdns-yy.net.

...etc., for the .org and .co.uk domains.

This delegates all lookups for that subdomain (e.g. "vendor") and all of its subdomains to the Route 53 servers, while leaving your existing servers authoritative for the records it still contains.

Then you can create records in the hosted zone in Route 53, including alias and CNAMEs as needed.

Michael - sqlbot
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  • Thanks for following up! I thought this too and I had tried to run with a config like this. When I run a NS test on this site i.e. https://www.whatsmydns.net/#NS/amazon.mydomain.com all the NS's return correctly for the subdomain. Looks good! But then if I test the A record https://www.whatsmydns.net/#A/amazon.mydomain.com it resolves to the correct IP for some of their test locations but not all. Then if I check in tomorrow, some of those servers which previous resolved correctly seem to drop off. Right now about 50% are resolving correctly, I'll check back in 48 hours! – Tom Jan 15 '16 at 17:48
  • Only 6 hours later and many of the DNS servers in the above test which were registering correctly have since changed to failed. It's like it works for a bit, then drops off and dies. – Tom Jan 16 '16 at 00:49