IPv6 Default Allocation - What size allocation are you giving out

Thu Oct 9 23:37:51 UTC 2014

On 10 October 2014 00:37, Roland Dobbins <rdobbins at arbor.net> wrote:

>
> On Oct 10, 2014, at 5:04 AM, Baldur Norddahl <baldur.norddahl at gmail.com>
> wrote:
>
> > NONE of the problems listed in RFC 6752 are a problem with using
> unnumbered interfaces.
>
> As far as Section 8 goes, you're even worse off than if you were using
> private IP addresses.
>

I see nothing in section 8 that is broken in my network. My public loopback
address is in DNS and reverse DNS works fine too.

>
> And see Section 9.
>

I see nothing in section 9 that is broken in my network. Traceroute works
perfectly. You do not get a string of * * * back. You get the IP of the
loopback which in turn goes through reverse DNS to tell you what router is
processing that step.

The only difference between a traceroute using unnumbered interfaces and
using numbered interfaces, is that you only get information about the
router and not the link.

> My point is that *analogous* issues arise with unnumbered interfaces.
> Loopback-only addressing isn't sufficient for troubleshooting purposes and
> other routine operational activities.
>

That is really up to me? 99% of my interfaces are unnumbered by the virtue
of being on access switches that simply have no layer 3 capability other
than management. Nobody is crazy enough to assign /30s to end users anymore
anyway. It is not my business to sell backbone links. I sell end user links
and those are unnumbered in my network and everyone else too.

I claim this argument is mostly BS. Information about link in traceroute is
nice to have. It is not need to have. I have never been in doubt of what
traceroute was telling me. Besides I have more effective methods to
troubleshoot my links.

> > The thing is that we will only use ONE public address for a router. And
> the router will be using that address for traceroute, ICMP et al. And
> therefore
> > RFC 6752 does not apply.
>
> Again, see Section 9.  *Analogous* issues arise in networks with
> unnumbered interfaces.  I'm aware that PMTU-D will work with the setup you
> propose.
>

That is not the only thing that works. Everything works. The only "problem"
anyone has been able to point to is that you lose link information in
traceroute and get host information in its stead. It is a small loss.

>
> You might want to take a look at Appendix A, too.
>

What about it?

That is incorrect.  You've been told repeatedly that troubleshooting
> unnumbered links is highly suboptimal; you've merely dismissed those
> arguments for reasons best known to yourself.
>

Maybe because on that one topic I am more an expert than you: I have
experience troubleshooting my network, you don't.

Regards,

Baldur