Re: whoami.akamai.net [was: Google Public DNS Problems?]

[Christopher Morrow <morrowc.lists () gmail com>]

On Thu, May 2, 2013 at 2:12 PM, Patrick W. Gilmore <patrick () ianai net>wrote:

> On May 02, 2013, at 12:12 , Joe Abley <jabley () hopcount ca> wrote:
> > On 2013-05-02, at 12:10, Joe Abley <jabley () hopcount ca> wrote:
> > > On 2013-05-02, at 11:59, Charles Gucker <cgucker () onesc net> wrote:
>
> > > >   That's not entirely true.    You can easily do lookup for
> > > > whoami.akamai.net and it will return the unicast address for the node
> > > > in question (provided the local resolver is able to do the
> > > > resolution).    This is a frequent lookup that I do when I don't know
> > > > what actual anycast node I'm using.
> > >
> > > Using 8.8.8.8 to tell me about whoami.akamai.net tells me what Akamai
> authoritative server Google last used to answer that query.
> > Oh, now that I poke at it, it seems like whoami.akamai.net is telling
> me about the address of the resolver I used, rather than the address of the
> akamai node I hit.
> > Never mind, I understand now :-)
>
> For clarity: Looking up the hostname "whoami.akamai.net" will return the
> IP address in the source field of the packet (DNS query) which reached the
> authoritative name server for Akamai.net.
>
> We use this to look for forwarding or proxying, which is frequently
> unknown / invisible to the end user.
>
> It has the side-effect that querying against an anycast server (e.g.
> 208.67.222.222 or 8.8.8.8) will show the unicast address of the anycast
> node which forwarded to our servers.
'the unicast address of the exit for upstream/cache-fill lookups' .. since
the topology behind the anycast node isn't necessarily:
    internet -> anycast-ip -|host|- unicast-ip ...

there could be some networking between |host| and the outside world, or
other things going on.

anyway... nit-picking-aside, cool that there's a way to figure this sort of
thing out :)
google has a similar method, which I can't find today :( <darn
webcrawler!!!>