round robin
WebReactor Networks
bind at webreactor.net
Sun Feb 17 14:19:14 UTC 2002
Today I am the fool. Sorry to post erroneous information based on ancient recollection rather than research, and thank you for the corrections. Thus I learn...
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From: Alan Sparks <asparks at quris.com>
Does on mine. BIND 8 (at least) rotates through A (and later revs any)
records. Problem can be when clients cache and fixate on one of the
addresses...
I have something like this on my name servers:
corpldap IN A 208.169.17.136
IN A 208.169.17.250
and dig shown alternate order on each query.
Don't use ping to test, use dig:
dig @nameserverip host.yourdomain.tld
Do it a few times, note the order of the returned records.
-Alan
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From: Len Conrad <LConrad at Go2France.com>
To: bind-users at isc.org
>More to the point, BIND does not do any round-robining.
To quote from your URL below:
"This is the current "round robin" function, and it has been used quite
successfully for several years in sharing load among several machines."
RRset-order default is "cyclic". dig any RRset 3 or 4 times and see the
physical order of the records change.
>BIND simply returns both of the A records.
but they both can't arrive exactly simultaneously, so they arrive in a
physical ordering.
>The client application chooses which of those A records to use.
could be, but vast majority is looking for one A record, and will take the
first in physical order.
>See < http://www.isc.org/products/BIND/docs/bind-load-bal.html > for more
>info.
I suggest you see it yourself.
Len
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From: Jim Reid <jim at rfc1035.com>
>>>>> ">" == WebReactor Networks <bind at webreactor.net> writes:
>> More to the point, BIND does not do any round-robining. Period.
This is utterly false. Period.
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From: Peter H%E5kanson <phn at icke-reklam.ipsec.nu>
WebReactor Networks <bind at webreactor.net> wrote:
> More to the point, BIND does not do any round-robining. Period. BIND simply returns both of the A records. The client application chooses which of those A records to use. In your case the "client application" is the Windows resolver.
Close. BIND by default returns all A records, the order between them is
randomized. This is controllable with the "rrset-order" statement in bind-9.
Next, what has been observed is that the ping command will do
one name lookup and then use the first address for all "pings".
Repeating the ping will most likley show a random selection ( unless
some vendor has created a "nameserver-cache". This cache should in
almost all cases be turned off and disabled)
> See < http://www.isc.org/products/BIND/docs/bind-load-bal.html > for more info.
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WebReactor Networks wrote:
>
> More to the point, BIND does not do any round-robining. Period. BIND simply returns both of the A
records. The client application chooses which of those A records to use. In your case the "client
application" is the Windows resolver.
>
> See < http://www.isc.org/products/BIND/docs/bind-load-bal.html > for more info.
>
> -------- Original Message --------
> Subject: RE: round robin
> Date: Fri, 15 Feb 2002 11:04:04 -0500
> From: "Haygood, David" <david.haygood at pgnmail.com>
> To: "'bind-users at isc.org'" <bind-users at isc.org>
>
> If your Windows Desktop is 2K or XP its cache is 24 hours.
>
> -----Original Message-----
> From: Brian Noecker [mailto:bnoecker at jabber.com]
> Sent: Wednesday, February 13, 2002 6:26 PM
> To: 'bind-users at isc.org'
> Subject: round robin
>
> Is there a trick for round robin to work correctly? I've got the following
> scenario:
>
> Two Bind 9.2.0 jailed servers, one master, one slave with either of the
> following A record options:
>
> test 10 A 10.2.2.1
> test 10 A 10.2.2.2
>
> or
>
> $TTL 2h
>
> test 10 A 10.2.2.1
> 10 A 10.2.2.2
>
> Now, on the both servers, they use themselves as primary DNS in resolv.conf.
> The master is on a solaris box, the slave a RH7.2 box.
>
> When I'm on the master itself and ping test, 10.2.2.1 is the only answer I
> get back. When I'm on a windows desktop using the master as its DNS server,
> I only get 10.2.2.1. When I'm on the slave server and ping, I get about a
> 30/70 split on my returns.
>
> Should I expect consistency on the round robin nature of Bind?
>
> Thanks in advance.
>
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