On 10 October 2014 00:37, Roland Dobbins <rdobbins@arbor.net> wrote:
On Oct 10, 2014, at 5:04 AM, Baldur Norddahl <baldur.norddahl@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