OT: DNS Failover

[Leonard Isham]

On 8/31/05, Mike McGrath <mmcgrath at iesabroad.org> wrote:
> 
> 
> > -----Original Message-----
> > From: fedora-list-bounces at redhat.com
> > [mailto:fedora-list-bounces at redhat.com] On Behalf Of Thomas Cameron
> > Sent: Wednesday, August 31, 2005 12:11 PM
> > To: For users of Fedora Core releases
> > Subject: Re: OT: DNS Failover
> >
> > > If you are looking for failover of the looked-up addresses, in many
> > > cases you can always give out multiple addresses by
> > including them as
> > > A records for the same name.  Browsers seem to be very good
> > at failing
> > > over on the client side if some of the returned addresses
> > don't work.
> >
> > Have you had success at that?  I've found that Windows
> > clients tend to cache DNS results no matter what your TTL is,
> > and to only use the first IP address they get until their
> > internal cache expires.  You basically have to run ipconfig
> > /flushdns to make a Windows box dump the IP address and
> > re-query the DNS server.
> >
> > Thomas
> >
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> >
> >
> 
> Its good to know that this isn't as simple an answer as it seems it
> should be, I'll be testing the multiple A record possibility over the
> next week or two, I'll post the results.  From what I understand having
> multiple A records can work in many occasions, but as far as DNS is
> concerned it wasn't designed to do that.
> 

You could consider a HA/load balancer implementation at a highly
redundant third party data center to front-end the real IPs/sites like
Ultra Monkey http://www.ultramonkey.org/.

Might be able to use openvpn.net in a HA setup in the third party data
center and NAT to hide the real destination.


-- 
Leonard Isham, CISSP 
Ostendo non ostento.