DNS Mystery in Heroku CNAME Redirection

Question

I have something quite mysteriously not working in my DNS configuration : - My app is at : `http://my-domain.herokuapp.com` I configured `my-domain.com` the following way : ``` @ 10800 IN A 174.129.25.170 www 10800 IN CNAME my-domain.herokuapp.com. ``` using wwwizer. So, `http://my-domain.com` redirects to `http://www.my-domain.com` which CNAMEs to `http://my-domain.herokuapp.com` Everything seems fine, but when I enter `http://my-domain.com` or `http://www.my-domain.com`, I get : `Heroku | No such app` error message. So I tried this : ``` host http://www.my-domain.com www.my-domain.com is an alias for my-domain.herokuapp.com. my-domain.herokuapp.com has address 54.243.92.108 ``` and ``` host http://my-domain.herokuapp.com my-domain.herokuapp.com has address 184.72.248.52 ``` I can't see where the problem is. WWWizer seems working fine, but it feels like CNAME hasn't refreshed since the herokuapp IP changed ... Any tip would be super appreciated. Thanks

Accepted Answer

Thanks to @neil-middleton comment, I found the solution.

I did added earlier `heroku domains:add my-domain.com`

but did not for `heroku domains:add www.my-domain.com`

which is the one that matters here. (Though I left both in case)

So it seems heroku has its own internal DNS control when CNAME-ing *.herokuapp.com where it gets as an entry the `heroku domains`.

This is logical to avoid setting CNAME to an app one don't own.

DNS Mystery in Heroku CNAME Redirection

Solution

Problem