Windows Azure uses elastic IPs. This means that the only way to map hostnames to Azure is to use CNAMES. The RFC is preventing us from doing this with the root of the domains.

mycooldomain.com IN CNAME myapp.cloudapp.net //this is invalid as the RFC
www.mycooldomain.com IN CNAME myapp.cloudapp.net //this is valid and will work

RFC isn't law. I want to do it anyway. What do I do?


3 Answers 3


See DNS Azure. It can keep your A records up-to-date so you don't need any CNAMEs.

  • There's no HTTPS anywhere on that site. Scary stuff,.
    – David Betz
    Oct 31, 2015 at 5:57

You just can't do it with DNS.

The DNS specification prohibits a CNAME from co-existing with any other resource records. Since your zone also needs NS and SOA records at its apex, you can't have the CNAME. RFCs may not be law, but I can assure you it won't work.

The only option is to have a web server listening on a specified IP (which should be on the A record for your zone apex) and then have that server do HTTP-level redirections to the www Azure site.


There is the proposed standard DNAME Resource record, described in RFC 2672. This would redirect your complete domain to another domain (which then would have to contain the lower-level domain names).

I'm not sure how good this is supported today.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .