Re:To www or not www
by teddyh on Saturday March 18, 2017 @06:26PM
(#13903818)
> If you want to be able to receive email on your domain, you’ll need to set MX records at the apex domain. With a CNAME, no other records can be set.
> Want to validate your domain for webmaster tools? Or for the DNS validation required for some domain validated SSL certificates? Now you have to add a TXT record to the apex domain. If you already have a CNAME, again, that’s not allowed.
It’s actually worse than that. All domains have, for technical DNS reasons, both a SOA record and at least one NS record in them at the “apex” domain. This would conflict with an apex CNAME record. Therefore, you can’t have a CNAME on an apex domain, even if it would otherwise be empty.
(There is a technical, and very theoretical, way around this limitation: The administrators of the top-level .com domain could, for example, add a CNAME record directly into the top-level domain zone. This would be valid, technically, but good luck convincing the various parties involved to do this.)
> Want to validate your domain for webmaster tools? Or for the DNS validation required for some domain validated SSL certificates? Now you have to add a TXT record to the apex domain. If you already have a CNAME, again, that’s not allowed.
It’s actually worse than that. All domains have, for technical DNS reasons, both a SOA record and at least one NS record in them at the “apex” domain. This would conflict with an apex CNAME record. Therefore, you can’t have a CNAME on an apex domain, even if it would otherwise be empty.
(There is a technical, and very theoretical, way around this limitation: The administrators of the top-level .com domain could, for example, add a CNAME record directly into the top-level domain zone. This would be valid, technically, but good luck convincing the various parties involved to do this.)