Sequence number arithmetic

[Cricket Liu]

On Thursday, February 6, 2003, at 12:45  PM, Fernando Gont wrote:

> Section 3.3.13 of RFC 1035 says:
>
> SERIAL  The unsigned 32 bit version number of the original copy
>         of the zone. Zone transfers preserve this value. This value
>         wraps and shuould be compared using sequence space
>         arithmetic.
>
> Does BIND not only check whether the primary's SOA serial number is
> higher than that of the local copy of the SOA record, but does some
> further comparision?
>
> I mean, I don't understand quite well what "sequence space arithmetic"
> a nameserver is expected to use. If the SERIAL field is expected to
> wrap, then I think the secondary would have to check whether the
> serial number of its SOA record is *equal* to that of the primary, and
> make a zone transfer whenever they are *different*.

You might read RFC 1982, "Serial Number Arithmetic."

cricket

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