rrset-order no longer supported in Bind 9.x ?

[Kevin Darcy]

There is no defined way to do "weighted round-robin" in DNS. BIND has no
support for this. I've experimented in the past with adding a
$WEIGHT master file directive to the BIND 8 code, but this was really
kludgey, and wouldn't propagate to slaves anyway, short of resorting to
some out-of-band method of zone replication.

SRV records have the ability to specify "weight", but no web browsers
implement SRV lookups yet. I can hardly blame them -- this is a substantial
change to the application logic. Some of us are lobbying to have
SRV support added to Mozilla (see
http://bugzilla.mozilla.org/show_bug.cgi?id=14328), but I don't have either
the time or the expertise to implement this myself. Any volunteers?

So the bottom line is: you're out of luck. You've been relying on an
illegal quirk of BIND to provide a feature of DNS, on the server-side, that
has been specified as a client-side function, but isn't actually
implemented in any clients yet.


- Kevin

Ian Northeast wrote:

> peter at icke-reklam.ipsec.nu.invalid wrote:
> >
> > Anthony Golia <Anthony.Golia at msdw.com> wrote:
> >
> > > It doesn't look like it, according to the doc.  Neither is
> > > multiple-cnames.  My company relied heavily on this.  Anyone know if
> > > there are any plans to support it in a future release?
> >
> > Your customer better change habits. Multiple cnames is A BAD IDEA
> >
> > Why try to do it the wrong way when the Right Way(TM) is available ?
>
> I have tried hard, and failed, to find the right way to replace:
>
> name IN CNAME s1
>      IN CNAME s2
>      IN CNAME s3
> s1   IN A     10.1.1.1
> s2   IN A     10.1.1.1
> s3   IN A     10.1.1.2
>
> So can anyone explain what it is? The object, if it is not obvious, is
> to have twice as many queries directed to machine 1 as 2. Machine 1 is
> twice as fast as 2 (the case is simplified).
>
> Apolgies if I'm being thick here but I have asked before and got no
> response.
>
> This works in bind8 with multiple-cnames and doesn't work at all in 9.
> I've tried a round robin with As and it still appears to be discarding
> duplicates. If it didn't do this all would be well. I have used this
> kludge with CNAMEs to get around this issue. If someone can tell me how
> to do this without breaking the rules I will be grateful. I cannot find
> it in the documentation. I really do not want to assign extra IP
> addresses to the faster machine, they are in very short supply.
>
> Regards, Ian