ISP network design of non-authoritative caches

Joel Baker lucifer at
Sun Nov 18 19:51:08 UTC 2001

On Sun, Nov 18, 2001 at 10:19:22AM -0000, Alex Bligh wrote:
> --On Saturday, 17 November, 2001 4:48 AM -0500 Sean Donelan 
> <sean at> wrote:
> > We know this isn't good engineering practice, because another national
> > ISP with millions of subscribers configured their network the same way,
> > and experienced a multi-hour service disruption affecting most of their
> > users a couple of years ago when an error blocked access to their two
> > caching-only, name servers.
> You mean there are national ISPs out there, who have exactly 2
> caching nameservers, as opposed to configure their clients with
> 2 IP addresses (perhaps always the same 2) which perform name
> resolution? Wow. Is this some sort of retro fashion?

Yes, there are.

No, it's not fashion. Though it's about as foolish.

Names avoided to prevent NDA lawsuits. You can fill in the blanks.
Joel Baker                           System Administrator -
lucifer at    

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