[CentOS] High Availability using 2 sites -- yep, "propogation."

[Bryan J. Smith]

Mickael Maddison <centos at silverservers.com> wrote:
> Hello Les,
> Forgive me for this sidestep, but you are saying that
> Windows/IE actually ignores bad IP addresses if a site
lists
> multiple IP's in a DNS lookup?  I tried this approach for
> some redundancy a couple years ago and it didn't seem to
work
> as you suggest.  If it has indeed changed to work that way,
> this will help one of my clients immensely.

No.  The Windows resolver does not work so well.  It's quite
the opposite.  The resolver and IP stack actually "holds
down" names and IPs depending on availability -- for the
_entire_ name.  It also varies based whether it is DNS or
ADS-integrated DNS.

There's about 2 dozen factors that I really don't want to get
into on a Linux -- most specifically RHEL/CentOS -- list. 
You can really hack around the registry and change the
attributes of the Windows resolver/stack, but at _no_ point
have I _ever_ seen the resolver, stack or apps like MS IE
ignore some IPs and use others, from DNS.

The only time I've seen MS IE do some interesting resolution
is for ADS -- using RPC services, _not_ DNS (even if it is
seemingly hitting a DNS server, it's ADS-integrated DNS and
works very differently, long story).


-- 
Bryan J. Smith     Professional, Technical Annoyance                      b.j.smith at ieee.org      http://thebs413.blogspot.com
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*** Speed doesn't kill, difference in speed does ***