On Dec 3, 2:14 pm, Sage <
sage...@gmail.com> wrote:
> So somehow i dont think it will be quicker than my local 24ms
> server... Even if the actual DNS retrieval is quicker..
The ping latency alone won't tell the whole story when it comes to
DNS. If the record you're requesting is in both your local DNS and in
Google's DNS, then yes -- local is going to be significantly faster.
If, however, the record isn't available in your local DNS but is in
Google's, and the request time between your local server and the next-
most authortative DNS is greater than the difference in latency
between your system and your local DNS and between your system and
Google's DNS, then using Google's DNS would be a better choice. And
if neither have the record you want, but Google can get it faster,
again you'll have a win for Google's DNS servers.
All of which means, depending on your browsing habits, you could have
a net win using Google's DNS servers. If you're mostly staying within
your LAN, or are hitting records that are likely to be cached (because
you only use a handful of popular sites), then Google probably won't
help much. If you're hitting lots of random obscure sites, Google's
DNS may have a net positive effect, even with a higher access latency
(as the lookup delay between the DNS servers may be significantly
lower).
In my case, I run my own DNS server. Doing some quick tests using dig
to measure the response time on some obscure, unlikely-to-be-locally-
cached domain names, Google's DNS is often coming back as faster than
having my local DNS contact the forwarding nameserver to resolve the
name. As such, even though Google's ping latency from my network is
higher than contacting my ISP's nameservers (the current forwarders),
the fact that they seem to be more heavily optimized towards reducing
latency during cache hits looks to be an overall win. As a forwarder
to my local DNS, this means that subsequent lookups for the same
domain are going to be virtually instantaneous (as they're cached by
the local DNS until their TTL hits). I'm going to make them my
preferred forwarder.
There are a lot of organizations that run their own caching DNS's that
do DNS forwarding; if Google's optimizations turn out to be all
they're cracked up to be, switching to using them for resolving
external names may be a win, even if the latency to the server is
higher. And if Google deploys more proximal servers, all the better
-- the gains will be immediate for anyone who relies on them for DNS
forwarding.
Yaz.