OT: 512KDay - dalsi strasak Y2K?
lukesh na seznam.cz
Středa Srpen 13 21:10:21 CEST 2014
512KDay: Why the internet is BROKEN (Next time, big biz, listen to your
We failed the internet's management challenge
By Trevor Pott, 13 Aug 2014
Yesterday, 12 August, 2014, the internet hit an arbitrary limit of more than
512K routes. This 512K route limit is something we have known about for some
The fix for Cisco devices – and possibly others – is fairly straightforward.
Internet service providers and businesses around the world chose not to
address this issue in advance, as a result causing major outages around the
As part of the outage, punters experienced patchy – or even no – internet
connectivity and lost access to all sorts of cloud-based services. The
LastPass outage is being blamed by many on 512KDay, though official
confirmation of this is still pending. I have been tracking reports of
inability to access cloud services such as Office365 through to more
localised phenomena from around the world, many of which look very much like
they are 512KDay related.
As an example of the latter, while I don't yet have official confirmation
yet from Canadian ISP Shaw, all indications are that the "mystery routing
sickness" which affected its network (and which continues at time of
publishing) could be related to the "512KDay" issue.
It looks like the issues I experienced with Shaw are likely down to routers
within Shaw hitting the 512K limit. These routers hit the magic number and
then were unable to route individual protocols (such as RDP, for example,
although we cannot confirm this is so in Shaw's case) to the Deep Packet
Inspection (DPI) systems that the ISP uses to create a "slow lane" enhance
our internet experience*.
As the fix for these issues can range from "applying a patch or config
change and rebooting a core piece of critical network infrastructure" to
"buy a new widget, the demand for which has just hit peak" there is every
chance that 512KDay issues will continue for a few days (or even weeks) yet
Others around the world have seen issues as well. Consider the issues
reported by Jeff Bearer of Avere Systems who says "my firewall started
noting packet loss between it and its upstream router. It wasn't that bad
until employees started showing up for work, but then it jumped up quite a
bit. We don't have any real evidence, but I did go back and forth with the
ISP several times. It looks like it probably was [the 512KDay event] that
Bearer asks a critical question: "Why wasn't this in the press, like Y2K or
Perhaps this is the ghost of Y2K. Globally, we handled the very real issues
posed by computers being unable to comprehend the passing of the millennium
so well that the average punter didn't notice the few systems that didn't
get updated. IPv4 has been a highly publicised apocalypse that has dragged
on for over a decade and the internet has yet to collapse.
512KDay is simply "yet another arbitrary limit issue" that has been for
years filed away alongside the famous Y2K, IPv4 or 2038 problems. If you're
interested in some of the others, Wikipedia has a brief overview of these
"time formatting and storage bugs" that explains the big ones, but doesn't
have a listing for all the known ones.
Do the media bear some of the blame? Perhaps. I have seen 512KDay issues
raised in many IPv4 articles over the years, but rarely has it been
discussed in a major publication as an issue in and of itself. Perhaps this
is an example of crisis fatigue working its way into the technological
sphere: as we rush from one manufactured "crisis" to another, we stop having
brain space and resources to deal with the real issues that confront us.
The finger of blame
One thing I do know is that it is the job of network administrators to know
about these issues and deal with them. What wasn't in the mainstream media
has been in the networking-specific trade press, in vendor documentation and
I have been contacted by hundreds of network administrators in the past 12
hours with tales of woe. The common thread among them is that they
absolutely did raise the flag on this, with virtually all of them being told
to leave the pointy-haired boss's sight immediately.
Based on the evidence so far, I absolutely do not accept the inevitable
sacrifice of some junior systems administrator to the baying masses.
Throwing nerds under the bus doesn't cut it. The finger of blame points
squarely at ISPs and other companies using BGP routers improperly all across
It's easy to make a boogyman out of ISPs; they're among the most hated
industries in the world, after all. It's easy to point the finger of blame
at companies that chose not to update their infrastructure because I've
spent a lifetime fighting that battle from the coalface and it has made me a
bitter and spiteful person.
Not my problem
Unfortunately, despite any understandable anti-corporate angst I might
maintain, 512KDay was completely avoidable, and – mark my words – this is
the beginning, not the end.
Another looming problem is IPv6. Millions of small and medium businesses
today use two internet links and a simple IPv4 NAT router to provide
redundancy and failover. Everything behind the NAT router keeps the same IP;
only the edge IP changes if things go pear-shaped.
With IPv6 NAT functionally banned by the ivory tower types who designed the
protocol, currently, there is no neat solution to this in IPv6. Existing
doctrine states that SMBs should simply get an AS number, get their own
subnet and then manage and maintain their own BGP routers, announcing routes
to both ISPs.
Putting aside for one moment that most SMB-facing ISPs won't allow BGP
across low margin links, the above 512KDay issues should demonstrate
adequately that the very concept is completely bleeping batbleep insane.
The largest companies in the world – and internet service providers around
the world – failed to listen to the best trained network engineers in the
world. Dolly's automated doughnut emporium and internet-driven robobakery is
not going to have talent or resources anywhere near what those organisations
have to offer.
Oh, there are proposals that state "in a perfect world where everyone throws
out every computer, router and application they have, everything will
understand the concept of multiple addresses, multiple paths, and
redundancy. Assuming we all agree on this RFC and then implement it." We
haven't all agreed on an RFC, and anyone who thinks the world is chucking
its entire installed base of IT to achieve in IPv6 what was a
fire-and-forget $150 dual-port WAN under IPv4 is barking mad.
Alternately, we could abandon the idea of maintaining address coherency
internal to our networks altogether and become utterly and completely
dependent on DNS, even integral to our own networks and even for such
critical bits of our infrastructure as basic management and diagnostic
And what if it all comes crumbling down?
Absolute DNS reliance is madness. DNS does fail. Even if you are made out of
super-macho certifications and have nerd cred that ripples like a
steroid-abusing superman's muscles at the gym. It fails for the same sorts
of reasons that 512KDay bit us in our collective proverbial: human error.
Human beings make mistakes. We make the wrong call. We don't spend money
where we should and we spend money where we shouldn't. Hindsight is 20/20
and foresight far more hazy, and sometimes we take what we think is an
"acceptable risk" only to have it turn out to be the thing that bites us.
If 512KDay should teach us anything, it is that no single point of failure
is acceptable, no matter the size of your business. Yet we also need to bear
in mind that not all businesses are Fortune 500 companies with the GDP of
Brunei to spend on networking every year.
If you bet your company on cloud computing to be the thing that enables you
to operate, there was a good chance that 512KDay was a cold splash of
reality when compared to the smooth marketing promises of unbeatable
reliability and 24/7 availability. What good is cloud anything if the
network connecting you to it fails?
In a similar vein, the series of bad and worse choices for SMBs looking to
implement IPv6 will lead many of them to choose single points of failure
even if they don't want to. Absolute reliance on DNS or a single ISP could
cost them in the future.
What of the other as yet unknown vulnerabilities? Arbitrary limits and the
design-by-fiat decisions that simply tell significant (but usually not
well-heeled) chunks of the world to take a hike? Will we, as an industry,
learn anything from 512KDay, or will we continue along as though nothing is
wrong, blaming anyone and everyone except those who actually have the
ability to affect change?
I leave you with a quote from Upton Sinclair: "It is difficult to get a man
to understand something, when his salary depends upon his not understanding
512KDay was avoidable. Will we choose to avoid the next one? Answers in the
comments, please. ®
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