Multiple default records

[Kvetch]

Thanks, I was looking into this because we use hardware load balancers for 
some of our sites but for the default records I wanted to see if there was a 
simpler way of achieving this type of failover.
That makes sense that it is up to the user's browser but I wasn't sure if 
there was anything in the round robin distribution method that accounted for 
this. I thought MX records were handled this way. If the preferred MX record 
fails it attempts to delivery to the next MX record.
Thanks,
Nick

On 8/31/05, John Wobus <jw354 at cornell.edu> wrote:
> 
> The DNS has nothing to do with whether there is
> actually anything at the address. It's just a database
> that (in this case) looks up names and gives
> out corresponding numbers. However, there
> are products that do what you suggest, checking
> webservers, and reconfiguring DNS servers
> (such as bind) accordingly.
> 
> The actual user experience is dependent upon
> what clients (IP stacks and browsers) do. Client
> software does whatever the coder thought
> worked best (as opposed to following any
> agreed-upon protocol), and the coders are
> often concerned with the avoiding huge numbers
> of lookups (e.g. gif images), thus they cache.
> Typical browser cache-time is a half hour.
> 
> Balancing load and handling fallback is a
> whole field, with lots of lively
> discussion, and products that cost
> substantial amounts of money. Probably
> more than you can imagine.
> 
> John
> 
> On Aug 31, 2005, at 2:42 PM, Kvetch wrote:
> 
> > Hello, I was wondering exactly what happens with a zone that has
> > multiple
> > default records and one of those records are unavailable.
> > For example if I have
> > foo.net <http://foo.net>. 60 IN A 192.168.1.1 <http://192.168.1.1>
> > foo.net <http://foo.net>. 60 IN A 192.168.1.2 <http://192.168.1.2>
> > foo.net <http://foo.net>. 60 IN A 192.168.1.3 <http://192.168.1.3>
> >
> > If a user visits foo.net <http://foo.net> <http://foo.net>'s website and 
> gets the
> > 192.168.1.1 <http://192.168.1.1><http://192.168.1.1>server, then 15 
> minutes they return to
> > foo.net <http://foo.net> <http://foo.net> but 192.168.1.1<http://192.168.1.1><
> http://192.168.1.1> had
> > crashed
> > during this 15 minute interval would they automatically be sent over to
> > 192.168.1.2 <http://192.168.1.2> <http://192.168.1.2> or 192.168.1.3<http://192.168.1.3><
> http://192.168.1.3> or
> > would they continue to round robin between the 3 IP's and might get a
> > 404
> > error if they hit 192.168.1.1 <http://192.168.1.1> <http://192.168.1.1>? 
> So basically does
> > DNS
> > recognize that one of the IP's is unavailable and send the user to
> > another
> > IP. Kind of like MX record's preference values.
> >
> > Since the TTL is 1 hour they would not have to return to our DNS server
> > since they received all 3 IP's, correct?
> >
> > Thanks,
> > Nick
> >
> >
> 
> 
>