[Freeipa-devel] [PATCH] 0024 - Better random ranges

[Stephen Gallagher]

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On 12/06/2010 06:51 PM, Simo Sorce wrote:
> 
> This patch reduced the size of the default range (from 1 million to
> 200.000) and also changes the way the range is selected.
> Instead of starting at a completely random number, it selects 1 out of
> 10000 random 200k ranges so that the range starts at multiples of 200k.
> 
> This makes it so that 2 different installs either do not overlap at all
> or overlap completely (once in 10k times) instead of potentially
> partially overlapping.
> 

Instead of using a random number here, why don't we do something more
predictable (so installing FreeIPA on the same machine will hit the same
range).

Something we used to do at my old job was base it on the IPv4 address of
the primary network adapter in the machine. Basically, we could take the
integer representation of the IP address, take the modulus 10000 of it,
and choose the range from that.

This would also provide a guarantee that replicas on the same network
would get unique ranges (instead of a 1 in 10,000 chance of doubling up).

These are just suggestions. The patch as it exists right now looks fine
to me (though I haven't tested it).

- -- 
Stephen Gallagher
RHCE 804006346421761

Delivering value year after year.
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