Re: strange ping and traceroute results

On 21 November 2016 at 18:20, Shachar Shemesh <[email protected]> wrote:

> The DNS resolving google.com guesses your gegraphical location, and gives
> you an answer that is nearest where you are. If you use another DNS to
> query the domain, you will get a different IP:
>

It's not always a "guess your geographic location". The smarter ones use
Anycast to advertise the same IP address from multiple locations on the
Internet and let BGP do its magic to route your packets to the nearest
server, taking into account any congestion or other transient connection
speed changes. This is how Google's DNS 8.8.8.8 works, or Akamai's CDN. The
nice thing about it is that you get optimal response even at the host
resolution stage. The DNS server can then take its knowledge of the DNS
query source address into account when it decides which IP address to
resolve to.

It's pretty neat, personally I find it a fascinating trick:
https://en.wikipedia.org/wiki/Anycast

--Amos
-- 
<http://au.linkedin.com/in/gliderflyer>

_______________________________________________
Linux-il mailing list
[email protected]
http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il