How can a DNS server confound IP geolocation?

Question

Most BBC on-line video content is blocked for IP addresses outside the UK. I recently beta-tested a service that gets round this block. All I had to do was change the DNS configuration on my laptop, and it just worked.

My understanding is that this system does not work like a VPN. Most of the content is streamed directly from the BBC's CDN to my laptop.

How does this work? And is it something that the BBC could block again if they wanted to?

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EDIT

To clarify: My understanding is that only the first megabyte of content passes through the DNS server. So for the initial "handshake" it does, indeed act like a VPN. But after that, the DNS server gets out of the way and somehow persuades the CDN to deliver content directly to an IP address in Japan.

Answer 1

Name names, please.

If the BBC does this like everyone else (and they do), it's based on the address of the client. No amount of DNS tricks will change what your IP is. HOWEVER, this can make for a "dns hijacking" "man-in-the-middle attack": Your DNS lookups are answered with IPs they control, thus you are connecting to them, not the BBC.

It's like a VPN, only through a process no sane person would trust -- as they can now trick you into connecting through them for almost anything.