IPv6 and CDN's

Sun Nov 28 13:07:03 UTC 2021

On 11/28/21 14:58, Masataka Ohta wrote:

> Exactly.
>
> That facebook poorly managed their DNS to cause the recent disaster
> is an important evidence to support my point that DNS, so often, may
> not be helpful for network operations against disastrous failures,
> including, but not limited to, DNS failures.

Yes, but that does not mean that DNS is not valuable, or cannot be 
hardened.

Everything can break, even an IPv4 interface on a router port. Good 
practice in network operations is what keeps these kinds of problems at 
bay. I mean, why else do we have lists like these?

I am certain Facebook have hardened their DNS infrastructure, and that 
particular failure scenario should not recur, given all the clever 
people there, and around them.

>
>> There was a time when knowing the IP(v4) address of every interface 
>> of every router in your network was cool.
>
> I surely acknowledge your point that it is impossible to do so with
> MAC address based IPv6 addresses, which is why IPv6 opex is so high.
>
> But, with manually configured IP addresses, it is trivially easy
> to have a rule to assign lower part of IP addresses within a subnet
> for hosts and upper part for routers, which is enough to troubleshoot
> most network failures.

That's just satisfying one's mental (or emotional) nits.

Routers (and customers) don't care about how anally we assign address 
space. As long as it is compliant, does not conflict, and is correctly 
routed.

That we cannot transpose our IPv4 mental/emotional habits on to IPv6 
does not make IPv6 more complicated. It just makes us more stuck in our 
ways.

After all, DHCPv6 still does not offer a default gateway.

> So, you are saying you haven't faced real operational problems
> to loss DNS information for these 15 years.
>
> Congratulations for your luck!

I am sure I have had a DNS issue of some sort or other in the past 15 
years. The fact that I can't remember what it was is telling.

> Surely, the recent disaster of facebook happened in the recent
> past.
>
> So what?

And they have learned from it, and I dare say, fixed it.

Facebook will neither be disposing of DNS any time soon, nor will they 
be dropping IPv6.

Mark.