Internet2 Network Security SIG

[Paul Howell <>]

I think this is a timely topic.  Resiliency in the  face of sever disruptions that essentially segment major networks is something we've been discussing inside of Internet2 and began promoting externally as well, doing a presentation at the DHS cyber security table recently on this topic.  As a follow up to the presentation, I'm writing an article for our newsletter that will come out later this month.  I am always interested in working together on this topic, perhaps we could have a security-wg call to discuss further.  Thoughts on that?

 

Regards,

Paul

 

 

From: <> on behalf of Steven Wallace <>
Reply-To: <>
Date: Friday, November 3, 2017 at 10:54 AM
To: Akbar Kara <>
Cc: Bill Owens <>, "" <>, NTAC <>, Kim Milford <>, "" <>
Subject: [Security-WG] Re: [NTAC] DNS Serving Stale to the rescue?

 

My scenario is loss of Internet connectivity. That would include loss of TR-CPS.

 

I think we need to be careful WRT to routes to roots. Roots are anycast, and since most of us local-pref TR-CPS/I2, this could lead to suboptimal DNS requests, both in terms of path used, and concentrating queries to fewer serves. This may already be happening. It would be good for someone to check the I2/CPS routing tables for the root anycast prefixes.

 

steve

On Nov 3, 2017, at 10:48 AM, Akbar Kara <> wrote:

 

Steve,

 

Could we not ask TRCPS to carry routes to root server infrastructure? Or is the assumption that campus has lost TRCPS too!

 

Alternatively, it would be interesting to run quagga on AWS vm (that has a path to commodity) and have quagga vm NAT packets originating from your campus DNS that are destined to external DNS.  Maybe something will break... One could do this test for the cost of a latte 😀

/ak

 

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On Nov 3, 2017, at 8:56 AM, Steven Wallace <> wrote:

In some of my uses cases, it ensure the resolver continues to have access to the authoritative name server.

 

For example, caching the TLD entry that points to canvas’s name server (which happens to be hosted in AWS), ensures my resolver is able to refresh its cache for canvas’s domain.

 

steve

 

On Nov 2, 2017, at 9:44 PM, Bill Owens <> wrote:

 

It sounds as though this would solve many problems in your isolated campus scenario, but I wonder about the side effects on providers who load balance by returning different DNS results. It’s not uncommon to see 60-second TTLs in records from cloud providers, sometimes even shorter. I think it is unlikely that the server behind whatever A record BIND decided to stick with would simply go away, but it is possible that server would be overwhelmed by the continuous load from your campus. It might be worth a discussion with your critical cloud providers, if they’re willing to discuss that ‘secret sauce’.

 

Bill.

On Nov 2, 2017, at 11:00 AM, Steven Wallace <> wrote:

It’s going to get better. BIND 9.12 (currently in beta, GA due out end of year?) supports “serve stale” (see: https://tools.ietf.org/html/draft-tale-dnsop-serve-stale-02). Serving Stale Data to Improve DNS Resiliency - does what you’d expect. If the resolver can’t update a cached entry, it responsed with the its current cached entry. BTW, this would have mitigated the October Dyn outage, which left many in the community without access to Box, PayPal, etc., despite the fact that we had working network paths to these service providers.