Re: [DNSOP] Draft for dynamic discovery of secure resolvers

"Livingood, Jason" <Jason_Livingood@comcast.com> Sun, 19 August 2018 13:18 UTC

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From: "Livingood, Jason" <Jason_Livingood@comcast.com>
To: Paul Vixie <paul@redbarn.org>, Ted Lemon <mellon@fugue.com>, dnsop <dnsop@ietf.org>, =?utf-8?B?TWFyZWsgVmF2cnXFoWE=?= <mvavrusa@cloudflare.com>
Thread-Topic: [DNSOP] Draft for dynamic discovery of secure resolvers
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Date: Sun, 19 Aug 2018 13:18:06 +0000
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Subject: Re: [DNSOP] Draft for dynamic discovery of secure resolvers
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In a DOCSIS network, for whatever that's worth, the link from the home (cable modem) to the next hop (CMTS) is encrypted. It is then usually just one or two hops within the ISP's regional network to the recursive DNS (in some cases DNSSEC-validating, as in our case). So I suppose that the threat model in this example is presumably someone (1) eavesdropping on the relatively short path between CMTS and resolver or (2) modifying non-DNSSEC-validated responses - and that's does not seem like a very high risk threat IMO, given all the other potential and real threats lurking around on the Internet. 

In any case, if a user felt it was a high risk then letting their stub pick up the same resolver address (such as via DHCP) and choose to use TLS to secure the DNS query stream to the same resolvers would seem like an easy solution. But I am sure there are countries where this might carry a higher risk, in which case users have traditionally used Tor, VPNs, etc. In the latter (user-directed) case this suggests an implementation model where an end user optionally turns something on rather than a 3rd party deciding it should always be on (given the likely downsides of this operationally).

- Jason

On 8/18/18, 8:54 PM, "DNSOP on behalf of Paul Vixie" <dnsop-bounces@ietf.org on behalf of paul@redbarn.org> wrote:

    my threat model is intruders or eavesdroppers on the path between me and 
    my rdns. i'd like the dhcp announcement to include a tcp/853 signal 
    along with a pre-shared key or the hash thereof. the benefit would be 
    that if my rdns network path is less secure than my dhcp network path, 
    i'll improve the former by not using traditional udp/53. does that help?
    
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