LOL... I don't know that they so much broke anything other than people's sanity and expectations. I can't say this with certainty, but I was always under the assumption that the DNS Client also respected TTL's of all RR's it cached. Maybe that was an incorrect assumption, but if that was correct then at most all they did was give everyone a caching stub resolver built into their OS. I don't feel this is much different than many *nix distributions installing BIND with a default recursive configuration and /etc/resolv.conf pointing to ::1 or 127.0.0.1... other than the obvious differences that it's doing recursion and you can *ASK* BIND what it's doing in a myriad of ways. That's always been my biggest gripe with the DNS Client. Either way, I wonder what the load on various DNS infrastructure throughout the world would look like if this mechanism didn't exist. I take it most recursive servers would just be answering a lot more queries from cache and burning cycles.
For the record, Mac OS X also caches DNS queries. You can flush with the cache with "dscacheutil -flushcache" up through Snow Leopard, or using "killall -HUP mDNSResponder" via sudo or equivalent root rights on Lion and Mountain Lion.
-Vinny
Jay Ashworth wrote:
Microsoft broke the Internet just to make their internal networking
work properly?
I'm shocked; *shocked* I tell... yes, just put the money right over there;
*shocked* I say.
You can't imagine how much time that lost me in diagnoses when it first
came out, until we finally located it somewhere on the Internet.
Yeah, SUNW did it even before MSFT. Ever heard about 'nscd'?!
It gets installed [but disabled by default] in any Linux distro derived
from Red Hat Linux as well. If activated, will keep resolved records
in an in-memory cache for an hour with all default settings.
Just an FYI...
Every version of Windows since Windows 2000 (sans Windows Me) has had
the DNS Client service which maintained this caching function. This was
by design due to the massive dependency on DNS resolution which Active
Directory has had since its creation. It greatly reduced the amount of
repetitive lookups required thereby speeding up AD based functions and
lessening the load on DNS servers. It still exists today up through
Windows 8. You can disable the service, but it will also break DDNS
updates unless your DHCP server registers hostnames on behalf of your
clients.
- -Vinny
DDNS updates (including WINS registrations), static updates, and Active Directory registrations are handled by the DHCPClient service since Windows 95 through all versions of client and server since. The DNSClient handles caching (in a method somewhat akin a very broken caching-only nameserver) only. You can disable the DNSClient service with no ill effect at all (actually, it will probably improve things significantly, if you have a local non-Windows caching recursive DNS to use). You cannot disable the DHCPClient service, however, without breaking DDNS updates, static configuration, and Active Directory.
Just an FYI...
Every version of Windows since Windows 2000 (sans Windows Me) has had
the DNS Client service which maintained this caching function. This was
by design due to the massive dependency on DNS resolution which Active
Directory has had since its creation. It greatly reduced the amount of
repetitive lookups required thereby speeding up AD based functions and
lessening the load on DNS servers. It still exists today up through
Windows 8. You can disable the service, but it will also break DDNS
updates unless your DHCP server registers hostnames on behalf of your
clients.
- -Vinny
DDNS updates (including WINS registrations), static updates, and Active Directory registrations are handled by the DHCPClient service since Windows 95 through all versions of client and server since. The DNSClient handles caching (in a method somewhat akin a very broken caching-only nameserver) only. You can disable the DNSClient service with no ill effect at all (actually, it will probably improve things significantly, if you have a local non-Windows caching recursive DNS to use). You cannot disable the DHCPClient service, however, without breaking DDNS updates, static configuration, and Active Directory.
You know, that's how I remembered it too, but I went to verify that before I posted and found different information so I thought I remembered wrong. Since you've affirmed my first instinct I'll retract what I said about DDNS and concur with your statement.
DDNS in Windows didn't exist before Windows 2000 (as AD also didn't), and Win9x operating systems didn't have services as I recall it, though. Admittedly, I thankfully haven't used a Win9x OS in a very long time.
-Vinny