> On 18 Oct 2019, at 10:11 am, 神明達哉 <jin...@wide.ad.jp> wrote:
>
> I have a question for which I believe there's an answer already that I
> couldn't find: what's the valid range for SOA REFRESH/RETRY/EXPIRE
> values?
>
> RFC1035 says:
>
> REFRESH A 32 bit time interval ...
> RETRY A 32 bit time interval ...
> EXPIRE A 32 bit time value ...
>
> and since it explicitly uses "unsigned" for SERIAL and MINIMUM, e.g:
>
> SERIAL The unsigned 32 bit version number of the original copy
REFRESH A 32 bit time interval before the zone should be
refreshed.
RETRY A 32 bit time interval that should elapse before a
failed refresh should be retried.
EXPIRE A 32 bit time value that specifies the upper limit on
the time interval that can elapse before the zone is no
longer authoritative.
> one obvious interpretation is that REFRESH/RETRY/EXPIRE are signed 32
> bit integers.
They are all intervals. How do you have a negative interval?
> And, since negative values for these don't make much
> sense, we might even interpret it similar to RR TTLs as clarified in
> RFC2181, i.e., 0 <= REFRESH/RETRY/EXPIRE <= 2^31-1.
>
> Is this correct? Implementations seem to vary on this point, btw.
> From my quick experiment with some code reading,
> - BIND 9 accepts any unsigned 32-bit values
> - Same for Knot
> - NSD treats them like TTL (values >= 2^31 are reduced to the "default
> TTL" value)
> (I've only checked at the primary side; I didn't do any test how the
> secondary side of the implementation uses these values when they are
> very large).
>
> Such huge values for these parameters don't make sense in practice
> anyway, so this is probably a pedantic question. But if anyone knows
> an authoritative reference that can answer it I'd appreciate it very
> much.
>
> Thanks,
>
> --
> JINMEI, Tatuya
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Mark Andrews, ISC
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