How does subdomain forward by domain registrar work?

Can you please help me understand how this particular functionality works:

I have a domain: example.com, it's registered with GoDaddy. its nameservers are set to linode: ie. ns1.linode.com, ns2.linode.com But at the same time, I can setup a subdomain redirect on GoDaddy and it works. So, I can create a 301 redirect from www. -> non www.

Can you please tell me how GoDaddy can do this?

From serverfault tarasm

• Just because your DNS is hosted by dyndns doesn't mean that GoDaddy isn't doing the web hosting. So you can tell your GoDaddy webhosting to perform the 301 redirect as long as the DNS records for www are pointing at GoDaddy's web servers.

  tarasm : Nameservers for this domain are pointing to Linode(ie. ns1.linode.com, ns2.linode.com) Godaddy is not hosting anything, except being the domain registrar.

  bortzmeyer : And who hosts the Web server?

  womble : @bortzmeyer: Precisely. @tarasm: What is the domain name, so we can investigate this for ourselves?
  From womble

• 301 Redirects are handled at the client-side. So when you redirect to something, no matter where it is hosted, the client will do the name lookup and go to wherever that resolves.

  tarasm : @Alex, I understand how 301 Redirect works. I'm trying to understand: "How the registrar has ability to setup a 301 Redirect, even though the DNS records are hosted on a completely different server and company."

  Alex : Perhaps I am misunderstanding the question. It doesn't matter who owns the name. You can 301 redirect to anything.

  tarasm : Yeah, that's not what I'm asking. I want to know how technically it works. What specific technology or aspect of networking functionality is giving Godaddy ability to do this.

  womble : @tarasm: The fact that the A record for whatever domain you're talking about is pointing at Godaddy's web servers.
  From Alex

• All sounds a little confused. From what I can interpret, from the GoDaddy domain manager you are able to cause www.example.com to 301 redirect to example.com.

  I'm fairly familiar with the GD domain manager and I don't recall this functionality. I would guess that:

  1. Your 301 redirect is coming from the site's hosting (.htaccess or whatever) rather than the domain hosting.
  2. One of GoDaddy's domain forwarding features is at play, in which case there is a misconfiguration.
  From Dan