I'm seeing the same thing. IIRC it was a mitigation measure by Akamai, perhaps to prevent new bots from joining the attack.
> I asked Akamai to redirect my site to 127.0.0.1 — effectively relegating all traffic destined for KrebsOnSecurity.com into a giant black hole.
Since Akamai was going to drop the "shields" on the site, instead of smashing the hosting provider with the attack, DNS was pointed at localhost.
With a simple script curling the page and looking at the content to check if it's pointed to the right server. Ignoring unroutable or inane IPs returned by the DNS.