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I'm not that familiar with the inner workings of DNS, preferring to just add my CNAMEs and A records as appropriate, and leave the behind the scenes to other services. I host a few sites on Amazon S3, which clearly doesn't allow you to have an A record with a specific IP as it is a cloud service. Consequently, I have to use 301 redirects for the naked ( domain to, enforcing the use of either a third party service, or a server to do the redirects.

I noticed that Cloudflare have started offering a service which allows you essentially to break DNS conventions and set a CNAME for your root domain - solving the naked domain on S3 issue. However, I'm not sure what the issues are with this - is this going to cause issues for MX records, web visitors and others? What could be the unintended side effects?

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up vote 3 down vote accepted

It's not really a CNAME, though, is it? It's a configuration of where they should pull your site from when they get requests for it.

CloudFlare's service directs traffic to their own servers as a caching proxy. Their example has a CNAME going to an Amazon EC2 address, but that's not the server they're going to point you to when your client queries for it; instead, they'll return the address of their own proxy host in response to your query.

If they did indeed configure a CNAME record on your root domain, it would indeed break your MX and SOA records - but I suspect that's not how they've implemented it.

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Sounds like some privacy issues may come into play if a proxy exists. Security issues too How is my data secured against unauthorized access in the cache?, also reliability issues What is the SLA for the cached proxy – LamonteCristo May 29 '12 at 19:00
@makerofthings7 Well, that's the service that CloudFlare offers; I'm sure their customers have asked the same questions. – Shane Madden May 29 '12 at 19:45
"it would indeed break your MX and SOA records" The biggest issue we have seen is with MX records (generally recommend setting A records for root domain) & this is largely a DNS RFC compliance issue. – damoncloudflare May 29 '12 at 23:34
@damoncloudflare Oh, so it is a direct CNAME from the client's domain to... well, is it a CNAME to your systems, or to the client's web hosting (as in the example in the linked blog post)? – Shane Madden May 30 '12 at 15:31

Any DNS server that permits such a configuration is buggy by definition. I wouldn't trust those DNS servers for any mission critical services.

On the other hand, this might work if Cloudflare owns all the servers for a given TLD (.biz, .com, etc) and then disallow any other record at such as MX, TXT, SOA, etc. This is unlikely, and would cause other problems down the road...

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