Need help on delegation to subdomain/external servers
RUOFF LARS
Lars.Ruoff at alcatel-lucent.fr
Thu Sep 17 16:05:28 UTC 2009
> [mailto:bind-users-bounces at lists.isc.org] On Behalf Of Kevin Darcy
[...]
> > I have a hot-swap redundant system where 1 out of 2 servers
> is active
> > at any given time and the other is standby. DNS is
> (mis?-)used to tell
> > the clients which one is active at a given moment.
> > The idea is that clients resolve a name of the server and
> the result
> > is the address of the server that is currently active. (Only the
> > current active server responds to DNS queries for its own name).
> >
> DNS isn't really suited to this.
I guess you are right, but that's how the system works. (it's not me who
designed it)
It's the only viable way to find out which one is active at a given
time.
[...]
> > The server uses TTL=0 in order to inhibit any caching on clients.
> >
> I hope this stays on a private network then, because TTL=0 is
> considered quite anti-social on the Internet. It makes
> everyone who queries your nameservers work significantly
> harder than they should.
It stays on a private network. :)
BTW, at the moment I am experimenting a solution usign a forward zone:
zone "dummy.ts" IN {
type forward;
forward only;
forwarders { 172.25.32.171; 192.168.2.3; };
};
It seems to work.
I guess that the requests are not sent simultaneously though?
What delay do I have to expect when only the second server (192.168.2.3)
is active?
What search policy is applied by default? (round-robin vs sequential?)
Can I modify it?
Obviously I would prefer a policy where we always forward to the last
active, unless we time out; Then try the alternate.
Will check that out.
Lars
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