DNS always updating
Kevin Darcy
kcd at daimlerchrysler.com
Thu Dec 4 01:30:22 UTC 2003
G Berg wrote:
>Hi there!
>
>Jim Reid wrote:
>
>
>> >> If I do not run my script and just reload the nameserver
>> >> without having made any changed to the zonefiles, he just
>> >> starts and then does nothing.
>>
>> >> So my question is: How does bind determine whether changes have
>> >> taken place to that he needs to send notifies and reload all
>> >> the files?
>>
>>The name server remembers the time when it last loaded a zone file.
>>On a reload, it compares that against the time that the filesystem
>>says the zone file was last changed. If the zone file is newer than
>>the timestamp when the server last loaded the zone, the zone gets
>>loaded again. So your script should be fixed so that it doesn't
>>generate new copies of zone files that haven't changed. You should
>>also consider generating the files in some other part of the
>>filesystem and then having the new or changed ones copied to the place
>>where the name server loads them. ie Don't generate the files directly
>>into the name server's working directory.
>>
>>
>>
>
>Thanks for your help.
>
>That was my thought as well and I changed my script so that only those
>zonefiles are created newly, which have to be modified. But this does
>not help.
>
Perhaps the problem is that you're doing a full reload. You can use
"ndc" to do zone-specific reloads for only the zones that have changed,
e.g. "ndc reload example.com".
>I guess the problem is, that my named.conf is rewritten every time. May
>this be true? I need to rewrite it since there may be zones added or
>deleted.
>
That too can be handled via "ndc": do an "ndc reconfig" after changing
named.conf if you want the running named process to notice newly created
or deleted zones. Do this before any reloads.
- Kevin
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