serial number format in dynamic dns update
Simon Hobson
shobson0309 at colony.com
Thu Oct 7 15:16:55 UTC 2004
Norman Zhang wrote:
> >RFC suggests that serial number in SOA, should be in
>>the format of YYYYMMDDnn.
>>
>>How dyn.dns updates the serial number using this
>>format?
>>
>>What is the next serial number using dyndns update, if
>>the current serial number is '2004103199'?
>
>I'm not sure if this has been discussed, Verisign is pushing for a new
>format.
>
>http://www.verisign.com/products-services/naming-and-directory-services/naming-services/page_005513.html
>
>In bind 9.2.3 and dhcp 3.0.1, I can only use yyyymmdd format. Is this by
>design?
Well with Bind 9.2.2 and dhcp 3.0.1 (what I'm running here) there is
no such constraint - DHCPD doesn't know or care what the serial
number is. As far as Bind is concerned (and I assume any RFC
compliant DNS server) the serial number is just a number, nothing
more, nothing less. If it HAPPENS to be something 'human friendly'
then that's a plus, but Bind just doesn't care - to it 2004100700 is
just a large integer (0x7774265c if I've got it right !). As long as
it keeps getting larger (whether by 1 to 2004100701 or by 100 to
2004100800) then no-one actually cares !
What verisign are saying doesn't affect this - they are merely
recognising that with the new update regime, they are likely to
exceed 100 updates/day and so the ddddmmyyxx format would break down,
so they are simply reverting to treating the serial number as a
number and have chosen to use the unix time in seconds which is a)
guaranteed to increase until 2038, and b) can be translated to a time
in case anyone did want to work out when an update occurred.
If you use DDNS, you CAN use yyyymmddxx (but the date will become
meaningless over a while), you CAN do the Verisign method, or you CAN
just start at ONE and keep incrementing - BIND DOESN'T CARE !
Simon
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Simon Hobson MA MIEE, Technology Specialist
Colony Gift Corporation Limited
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