Janus TCP/IP Base V7.8 changes: Difference between revisions

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The following features are new or changed in <var class="product">[[Janus TCP/IP Base]]</var>.
Content moved to M204int page of same name, but history preserved here.
==DNS Retries==
Prior to <var class="product">[[Sirius Mods]]</var> Version 7.8,
the <var>[[JANUS NAMESERVER]]</var> command had no facility to call for a retry of
a DNS UDP packet for which no response is received.
This meant that if <var class="product">Janus</var> does a DNS lookup just when the target nameserver
is down for an instant, or if the UDP packet gets lost on the network (IP
networks don't have to guarantee delivery of IP packets), the DNS lookup
could fail.
The version 7.8 "DNS Retries" feature is
a <var>RETRIES</var> parameter for the <var>JANUS NAMESERVER</var> command.
Setting <var>RETRIES</var> to a positive integer value, say 2, instructs <var class="product">Janus</var>
to retry as many as two times if no response was received to a DNS lookup.
Setting <var>RETRIES</var> to 0, its default, means no retries are attempted.
On a swamped network, it is probably better to
set a <var>JANUS NAMESERVER TIMEOUT</var> value of, say, 3 and a <var>RETRIES</var> setting of 2, rather than to set <var>TIMEOUT</var> to 10 with <var>RETRIES</var> at 0. This is so because:
*If a packet gets dropped, there is no benefit to waiting 10 seconds instead of 3.
*It is very unlikely that it would take a nameserver 3 seconds to respond to a received request (including packet turnaround time).
It probably does not make sense to set <var>RETRIES</var>
to a value greater than 2: if packets are being dropped so frequently
that three consecutive DNS requests are dropped, you have problems much more serious than the failed lookups.
 
{{Template:Content index: V7.8 Release Notes}}

Latest revision as of 21:50, 17 October 2013

Content moved to M204int page of same name, but history preserved here.