[LINK] DNS outage?
gdt at gdt.id.au
Wed Jul 29 09:00:33 AEST 2009
[my view, not my employer's]
On 29/07/09 08:09, Jan Whitaker wrote:
> What ever happened to the Internet rerouting itself so it 'can't be
> broken'? Or was that always a myth? I thought its resilience was one
> of its big selling points.
It's not a myth. But rerouting implies that the money has been spent
on putting in place an alternative. Some ISPs save money by not having
invested in redundant links, multiple sites, redundant routers and so on.
That is particularly so in the last mile of the infrastructure, and I
very much hope this is one thing the NBN will fix.
And then there's the problem of the rerouting mechanisms themselves not
being redundant. If you misconfigure BGP then no amount of physical
redundancy will save you. There are theoretical routing protocols which
survive misconfiguration, and a practical deployment of one of those
is becoming increasingly attractive. Although most big ISPs are moving
to database-driven networks, and the automated configuration of those
removes the risk of typos and so on. Leaving only the grand error :-(
For a long time I've advocated DNS servers being configured as anycast
services -- so that DNS forwarders are usefully redundant. For the
Glen Turner <http://www.gdt.id.au/~gdt/>
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