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On 4/5/2011 8:23 AM, <a class="moz-txt-link-abbreviated" href="mailto:iharrathi.ext@orange-ftgroup.com">iharrathi.ext@orange-ftgroup.com</a> wrote:
<blockquote
cite="mid:4561_1302006223_4D9B09CF_4561_5234_1_4FA354E0A9360042BED13414F9559F7106F9B5955D@PUEXCB1B.nanterre.francetelecom.fr"
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<div><font face="Arial" size="2"><span class="565521512-05042011">Hi,</span></font></div>
<div><font face="Arial" size="2"><span class="565521512-05042011">can
i make priority on a A or NS record? Since with round robin
if i put the same record record 2 or 3 time, Bind ignore
the duplicates Records, means</span></font></div>
<div><font face="Arial" size="2"><span class="565521512-05042011"> this:</span></font></div>
<div><font face="Arial" size="2"><span class="565521512-05042011">
<pre><p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="" lang="EN-GB"><font size="3"><font face="Times New Roman">wikipedia<span style=""> </span>NS<span style=""> </span>ns2.wikimedia.org.<o:p></o:p></font></font></span></p><p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="" lang="EN-GB"><font size="3"><font face="Times New Roman">wikipedia<span style=""> </span>NS<span style=""> </span>ns0.wikimedia.org.</font></font></span></p><p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="" lang="EN-GB"></span> </p><p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="" lang="EN-GB"><font><font face="Times New Roman"><font size="3"><span class="565521512-05042011">is the same like this:</span></font></font></font></span></p><p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="" lan
g="EN-GB"><font><font face="Times New Roman"><font size="3"><span class="565521512-05042011"></span></font></font></font></span> </p><span style="" lang="EN-GB"><font><font face="Times New Roman"><font size="3"><span class="565521512-05042011"><p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="" lang="EN-GB">wikipedia<span style=""> </span>NS<span style=""> </span>ns2.wikimedia.org.<o:p></o:p></span></p><p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="" lang="EN-GB">wikipedia<span style=""> </span>NS<span style=""> </span>ns0.wikimedia.org.</span></p><span style="" lang="EN-GB"><p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="" lang="EN-GB">wikipedia<span style=""> </span>NS<span style=""> </span>ns0.wikimedia.org.<o:p></o:p></span></p><
o:p></o:p></span><p class="MsoNormal" style="margin: 0cm 0cm 0pt;"> </p><p class="MsoNormal" style="margin: 0cm 0cm 0pt;"> </p><p class="MsoNormal" style="margin: 0cm 0cm 0pt;"> </p><p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span class="565521512-05042011"><font face="Arial" size="2">In this 2 case it will send 50% of traffic to ns2 and 50% to ns0;</font></span></p><p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span class="565521512-05042011"><font face="Arial" size="2">Is there anyway to enable priority on A or NS record?</font></span></p><p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span class="565521512-05042011"><font face="Arial" size="2">Thanks.</font></span></p></span></font></font></font></span></pre>
</span></font></div>
<br>
</blockquote>
For NS records, there is no way to do this in BIND, and it's
completely unnecessary anyway, since every major DNS full-resolver
implementation will keep track of how fast nameservers respond --
based on round-trip times, known as "RTT"s -- and prefer
faster-responding nameservers over slower-responding ones. So the
load spreads itself automatically, and failures -- which are
assessed as really "bad" performance -- are routed around.<br>
<br>
For A/AAAA records, there are mechanisms to control the order in
which the records are presented. See "sortlist" and "rrset-order"
(not sure that "rrset-order" even exists in later versions of BIND,
since I've never used it in production). However, these are only
practical on tightly-controlled intranets, where all of the
BIND-instance configurations can be kept in sync with each other,
otherwise one BIND instance may undo the careful address-record
ordering that another performs. rrset-order and sortlist are pretty
much useless for Internet names, since the vast majority Internet
users get their DNS through intermediate resolvers, which will
usually randomize or round-robin the responses whenever they are
answering from their caches.<br>
<br>
As another poster pointed out, SRV records provide the capability
for the domain owner to implement per-name failover and "weighting"
of targets, in the DNS data itself. But, thusfar the DNS community
hasn't had much success getting client-software developers (e.g.
browser developers) to adopt SRV record support. Meanwhile, certain
network-hardware companies (including among others a certain huge
router vendor) rake in big money with their sledgehammer
"load-balancer device" approach to the problem. There are software
approaches to network load-balancing as well, but I have no direct
experience with those.<br>
<br>
- Kevin<br>
<br>
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