On Thu, May 2, 2013 at 2:12 PM, Patrick W. Gilmore <patr...@ianai.net>wrote:
> On May 02, 2013, at 12:12 , Joe Abley <jab...@hopcount.ca> wrote: > > On 2013-05-02, at 12:10, Joe Abley <jab...@hopcount.ca> wrote: > >> On 2013-05-02, at 11:59, Charles Gucker <cguc...@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!!!>