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<div class="moz-cite-prefix">On 7/1/2012 2:42 PM, J P wrote:<br>
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Hello all!<br>
<br>
I understand RFC compliant DNS servers use AXFR and IXFR for
synching bewteen masters and slaves... and that this is the
general scenario for that purpose.<br>
<br>
However, I need somebody to technically explain to me why cant I
use a DNS resolver daemon such as the pdnsd dns proxy daemon
with a cache of for example 5 minutes... so I can configure it
to forward requests to my master (where I feed and store my
zones), with the cache being 5 minutes then iam sure the latency
between my master and the proxy will be minimal. <br>
<br>
Is this possible why yes or why not.<br>
<br>
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</blockquote>
I don't really know much about pdnsd, so I have a simple question
for you: does pdnsd answer with the AA (authoritative answer) bit
set or not?<br>
<br>
If it does, and it doesn't have a full copy of the zone at all
times, then it is violating the DNS spec and all bets are off as to
how well that will play with iterative resolvers.<br>
<br>
If it doesn't, then its answers are likely to be rejected by
iterative resolvers, who want to see that bit set on the responses.<br>
<br>
The bottom line is: don't pretend to have a full, replicated copy of
the zone if you don't have a full, replicated copy of the zone. Now,
strictly speaking, you don't have to use AXFR/IXFR to do the
replication -- some people prefer configuring all their "slaves" as
"type master" in named.conf and then using some other
non-DNS-standards-defined method to do the replication (e.g. rsync
or scp, combined with a "rndc reload" to read the contents back in
each time). Many commercial DNS management products use other
methods to replicate the data (QIP uses its "message" subsystem;
Infoblox uses "grid replication"). But calling a mere cache or
"proxy" a "slave" is just asking for trouble...<br>
<br>
- Kevin<br>
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