Two questions about the name server address sorting functiona lity

[Johan Larsson (EAB)]

Hi again!

Thanks for your answer. Regarding my second question I have a test case that gives
me some kind of address sorting even if I have no sort list configured:

In this test case I get seven IP addresses in the response. 
Normally these addresses are returned in a round robin way (actually random-cyclic in 9.1.3).
But in this case the IP address 10.43.2.95 belongs to the same subnet as an interface on my DNS server.
And as seen this address is always prioritized in the answer (no round robin).
Why is that if there are no default sortlist in BIND 9.1.3?

Best Regards,
Johan Larsson

Enter hostname or 'quit' to exit: dual5
Official hostname: dual5.bitlab.erv.ericsson.se
        address: 10.43.2.95
        address: 10.233.233.233
        address: 214.43.152.6
        address: 214.43.152.7
        address: 10.43.2.79
        address: 10.43.2.96
        address: 10.43.2.97


Enter hostname or 'quit' to exit: dual5
Official hostname: dual5.bitlab.erv.ericsson.se
        address: 10.43.2.95
        address: 10.43.2.79
        address: 10.43.2.96
        address: 10.43.2.97
        address: 10.233.233.233
        address: 214.43.152.6
        address: 214.43.152.7


Enter hostname or 'quit' to exit: dual5
Official hostname: dual5.bitlab.erv.ericsson.se
        address: 10.43.2.95
        address: 10.43.2.96
        address: 10.43.2.97
        address: 10.233.233.233
        address: 214.43.152.6
        address: 214.43.152.7
        address: 10.43.2.79

-----Original Message-----
From: Mark.Andrews at isc.org [mailto:Mark.Andrews at isc.org]
Sent: tisdag den 24 september 2002 00:09
To: Johan Larsson (EAB)
Cc: bind-users at isc.org
Subject: Re: Two questions about the name server address sorting
functionality 



> 
> Hi!
> 
> I'm running a BIND 9.1.3 nameserver and I have some questions about the addre
> ss sorting functionality of the name server, which sometimes seems a bit stra
> nge to me.
> 
> 1. When I have a sort list configured and I get a response containing multipl
> e IP adresses, any address matching an entry in the sort list should be prefe
> rred to the others. But if no IP addresses in the response matches any entry 
> in the sort list, it seems that the IP addresses are still returned in the sa
> me order, hence disabling the round-robin feature. Is this the correct behavi
> our?

	You will need BIND 9.3 to get this fix.

1224.   [bug]           'rrset-order' and 'sortlist' should be additive
                        not exclusive.

> 2. In "DNS and BIND", 4 ed. page 277 it says that BIND 4.x name servers have 
> a "default sortlist". I thought this behaviour was no longer present in BIND 
> 9.1.3., but it seems to me that if one of the IP addresses in a response belo
> ngs to the same subnet as any IP address of my DNS server, this IP address is
>  preferred to the others. If this is the case, is there any way to turn off t
> his behaviour?

	There is no default sortlist.
 
> Best Regards,
> Johan Larsson
>   
> 
--
Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at isc.org