'Today' considers data retention and IMP

[Florian Weimer]

* Igor Mozolevsky:

> Google's DNS servers reply differently based on
> the source address of the packet

fw@deneb:~$ dig +noall +answer www.google.com
www.google.com.         579981  IN      CNAME   www.l.google.com.
www.l.google.com.       247     IN      A       209.85.129.99
www.l.google.com.       247     IN      A       209.85.129.104
www.l.google.com.       247     IN      A       209.85.129.147
fw@deneb:~$ ssh albireo dig +noall +answer www.google.com
www.google.com.         589319  IN      CNAME   www.l.google.com.
www.l.google.com.       259     IN      A       74.125.77.103
www.l.google.com.       259     IN      A       74.125.77.104
www.l.google.com.       259     IN      A       74.125.77.147
www.l.google.com.       259     IN      A       74.125.77.99
fw@deneb:~$

deneb and albireo are about 70km apart.

Doing this redirection in DNS is the cheapest and most reliable way
(in the sense that geo-targeting errors degrade services and do not
completely break them).