New answers tagged cname-record
The browser passes the name its user is requesting in the http-header, regardless of what IP/CNAME the DNS returns to send the request to. It does not care what type of DNS record was used to resolve the name to an ip address. The CNAME does magically turn the browser into a http-forward-agent that changes its user's requested string into something else. So ...
CNAMEs from root to a subdomain are not good, but the reverse seems harmless. You can create a CNAME for www as you described and DNS should be ok. But now I can hit your site as example.com or www.example.com. This may not be as neat as your client desires. A better solution would be to create an A record for www which points at a redirect server which ...
Creating cname for root domain is not permitted by rfc.
Yes, you can do this, you'd just need to set up your current hosting to listen for subdomain.domain-name.com, and then set up an (A) or (CNAME) record in the DNS control panel for domain-name.com which points to the IP address assigned by your current host. If you're setting it up as an (A) record, be wary that in the future if your current host changes IP ...
The best solution to this problem that I can think of would be to have a full screen <iframe> on a.X.com that loads a.Y.com. Note that this will break bookmarking, so you may want to consider the pros and cons.
A CNAME should work the way you want it to as long as the application is not accessed using TLS/SSL, and uses relative rather than absolute URIs for its internal links. But a SaaS application certainly should use TLS, and if it does then you'll get a certificate name mismatch warning in the browser, since the certificate will be for a.y.com (or *.y.com) and ...
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