Sanjeev Gupta ghane0 at
Mon Jul 4 01:25:04 UTC 2016

On Mon, Jul 4, 2016 at 2:50 AM, Hal Murray <hmurray at> wrote:

> Is there any good writeup on why BCP-38 is so hard to implement and/or why
> it
> isn't implemented more often?  I assume it's money.  Is the problem routers
> can't do it?  (fast enough)  Or maybe ISPs don't have their act together?

Speaking with my Data Centre consulting hat on, the reason seems to be that
BCP-38 requires me to spend resources, but it is my neighbours that benefit.

However, despite that, things are much better than they were in 2006.
About 80% of the IPv4 space is behind gateways that implement BCP-38 (this
figure has been constant since about 2012).  See:

It is not hardware (trivial load), or configuration (low maint once set
up), it is simply that the cost-benefit ratio is horrible.  Costs are low,
but benefits are zero (or even negative, if you see your industry as a
zero-sum game).

Sanjeev Gupta
+65 98551208
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