DNS load balancing with CNAME possible?
John Wrate
lolo8000 at hotmail.com
Thu Apr 21 03:17:20 UTC 2005
David Botham <DBotham at OptimusSolutions.com> wrote in message news:<d4694t$1fsb$1 at sf1.isc.org>...
> bind-users-bounce at isc.org wrote on 04/16/2005 01:18:24 PM:
> > Hi all.
> >
> >
> > I have 2 dsl connections with dynamic ip addresses which have ports 25
> > and 110 forwarded to the same host. I want to balance the load between
> > the two dsl Internet connections by doing this:
> >
> > pop.mydomain.com. 300 IN CNAME dsl1.gotdns.com.
> > IN CNAME dsl2.gotdns.com.
>
>
> These entries will not work. What is on the left side of a CNAME RR
> cannot be on the left side of any other RR's in the name space. In your
> example, the second RR would constitute a second RR with the same left
> side.
>
> >
> >
> > But, the gotdns.com domain is not managed or hosted by me. What it is
> > is a free service (by dynip.org) where I have registered and that will
> > update the ip address of either of the dsl connections in case my ISP
> > changes it.
> >
> > Is it possible to do this? I tried and my dns will only resolve for
> > pop.mydomain.com with the last CNAME in the list. Is there any way to
> > do this and if so what am I doing wrong? When I use ip addresses (A
> > type records) it works very nice.
>
> Two A RR's would be your only choice.
>
> All of that being said, round robin DNS is probably not going to be an
> effective way to perform load balancing of inbound traffic on different
> links. You may want to look into an appliance that is designed for this
> purpose. F5 Link Controller and Radware LinkProof are two devices that
> come to mind quickly. I am sure there are others.
>
>
> >
> > Finally, my named server is running on a Linux host and while I
> > haven't yet figured out how to know the bind version, the man pages
> > displays "4th Berkeley Distribution"
>
> Try this at the command prompt:
>
> dig chaos txt version.bind @127.0.0.1
>
>
> hth,
>
>
> Dave...
>
>
> >
> > Any help will be appreciated.
> >
> >
Thanks a lot Dave. I will look into those devices.
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