Re: [dns-operations] anybody awake over at comcast.net?

2021-02-09 Thread Peterson (AWS), Alec via dns-operations 
--- Begin Message ---
OK fair point, will get with the team and we’ll figure out what skew we’re 
factoring in.  Thanks for that.

Alec

> On Feb 9, 2021, at 7:57 PM, Matt Nordhoff  wrote:
> 
> CAUTION: This email originated from outside of the organization. Do not click 
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> 
> 
> 
> On Wed, Feb 10, 2021 at 3:47 AM Peterson (AWS), Alec
>  wrote:
>> Hey Matt, sorry we missed your forum post, we do need to stay on top of 
>> those.
>> 
>> There are actually 2 hours of overlap, not 1.  For the zone I just provided, 
>> here is the previous and current RRSIG:
>> 
>> DNSKEY 13 2 3600 2021020901 2021020815 38680 hilander.com. 
>> J5WR2nU1Gl3xI5ehHBsnI7OXiThuYZKc1XpV6brYf85BgurOcZkb5+6eLbsvV+ykODaPrEnEIDu/HRYcaIRrNg==
>> DNSKEY 13 2 3600 2021020909 2021020823 38680 hilander.com. 
>> 735uL43A++phhPv/edwq02zANvAfEsas1j9HM+ghe+t7b6FLCAF6RZfXA9L+TBukYmhIkPiF87GbHDWXmETBNQ==
>> 
>> So when we roll the signature over, the one that we were previously using 
>> still has 2 hours of validity, not 1 hour.  So using your example, we would 
>> roll it over at 2300, not , giving us room for 1 hour of clock skew.  
>> Think that’s reasonable.
>> 
>> Alec
> 
> I haven't looked recently, but when I checked some poor customer's
> domain at 2020-12-31 23:59:59, that wasn't the case. It returned the
> 2020-12-31 15:00:00 - 2021-01-01 01:00:00 records:
> 
> <https://gist.github.com/mnordhoff/02e173d419387c3098cd0f90c7b75f34>
> 
> If the record rollover has been moved back one hour, the inception
> should correspondingly be moved back to 06:00:00 / 14:00:00 /
> 22:00:00, though. :-D
> 
>> On Feb 9, 2021, at 7:37 PM, Matt Nordhoff  wrote:
>> 
>> CAUTION: This email originated from outside of the organization. Do not 
>> click links or open attachments unless you can confirm the sender and know 
>> the content is safe.
>> 
>> 
>> 
>> On Wed, Feb 10, 2021 at 1:44 AM Peterson (AWS), Alec via
>> dns-operations  wrote:
>> 
>> +1 for short RRSIG times and the discipline it enforces.  We went down this 
>> path when building DNSSEC for Route 53, ZSK signatures are on the order of 
>> 10 hours:
>> 
>> hilander.com. 3599 IN RRSIG DNSKEY 13 2 3600 2021021009 (
>> 2021020923 38680 hilander.com.
>> 3H3QZt3qC2XbqkbumqsvRVeVrtgJVVRVGC/TZkc7vMuN
>> IdlL/wZrw+qBfYaSOex7dOp2PUP7pwW+NUgCXc2F7Q== )
>> 
>> A bunch of risks with this approach that needs to be mitigated, especially 
>> around static stability in the face of an issue with the ZSK signing 
>> process.  But all solvable.  As part of this we also automated ZSK rotation 
>> (which happens less often, but still on the order of once a week).
>> 
>> 
>> Speaking of which, the DNSKEY RRSIG lifetime should be 11 hours, not
>> 10 hours. The current expiration doesn't allow for client caching plus
>> clock skew. E.g.:
>> 
>> 23:59:59: Recursive resolver queries authoritative servers for
>> hilander.com DNSKEY, gets back record set with TTL 3600, RRSIG
>> inception 15:00:00, expiration 01:00:00.
>> (00:00:00: Authoritative servers switch to new DNSKEY record set, TTL
>> 3600, inception 23:00:00, expiration 09:00:00.)
>> 00:59:58: Validating stub resolver queries recursive resolver for
>> hilander.com DNSKEY. gets back cached record set with TTL 1, RRSIG
>> inception 15:00:00, RRSIG expiration 01:00:00.
>> 
>> If the stub resolver's clock is 3 seconds fast -- 01:00:01 -- and it
>> doesn't make an extra allowance for expired records or clock skew, it
>> will treat the record set as bogus.
>> 
>> (All other records except for DNSKEY are live signed, with the RRSIG
>> expiration set 1 hour after the TTL.)
>> 
>> <https://forums.aws.amazon.com/thread.jspa?threadID=05=0>
>> 
>> On Feb 8, 2021, at 9:27 PM, Paul Vixie  wrote:
>> 
>> CAUTION: This email originated from outside of the organization. Do not 
>> click links or open attachments unless you can confirm the sender and know 
>> the content is safe.
>> 
>> 
>> 
>> On Mon, Feb 08, 2021 at 01:45:06AM -0500, Viktor Dukhovni wrote:
>> 
>> ...
>> I do not recommend either X.509 certificate or RRSIG lifetimes quite
>> this long.  Shorter lifetimes IMHO promote better discipline.
>> 
>> 
>> for my own zones i think i'm using one year signatures and regenerating them
>> from "cron" once per week -- just to be safe. so, not better discipline 
>> unless
>> you deliberately _live_ on the edge, which i think is an unwise practice.
>> 
>> i expect i'll crib together some bourne shellack to check my whole signature
>> chains and warn me when there's less than 72 hours remaining in any validity
>> period. going into SERVFAIL like this is an operational risk i shouldn't 
>> take.
> --
> Matt Nordhoff


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Re: [dns-operations] anybody awake over at comcast.net?

2021-02-09 Thread Peterson (AWS), Alec via dns-operations 
--- Begin Message ---
Hey Matt, sorry we missed your forum post, we do need to stay on top of those.

There are actually 2 hours of overlap, not 1.  For the zone I just provided, 
here is the previous and current RRSIG:

DNSKEY 13 2 3600 2021020901 2021020815 38680 
hilander.com<http://hilander.com>. 
J5WR2nU1Gl3xI5ehHBsnI7OXiThuYZKc1XpV6brYf85BgurOcZkb5+6eLbsvV+ykODaPrEnEIDu/HRYcaIRrNg==
DNSKEY 13 2 3600 2021020909 2021020823 38680 
hilander.com<http://hilander.com>. 
735uL43A++phhPv/edwq02zANvAfEsas1j9HM+ghe+t7b6FLCAF6RZfXA9L+TBukYmhIkPiF87GbHDWXmETBNQ==

So when we roll the signature over, the one that we were previously using still 
has 2 hours of validity, not 1 hour.  So using your example, we would roll it 
over at 2300, not , giving us room for 1 hour of clock skew.  Think that’s 
reasonable.

Alec

On Feb 9, 2021, at 7:37 PM, Matt Nordhoff 
mailto:mnordh...@gmail.com>> wrote:

CAUTION: This email originated from outside of the organization. Do not click 
links or open attachments unless you can confirm the sender and know the 
content is safe.



On Wed, Feb 10, 2021 at 1:44 AM Peterson (AWS), Alec via
dns-operations 
mailto:dns-operati...@dns-oarc.net>> wrote:
+1 for short RRSIG times and the discipline it enforces.  We went down this 
path when building DNSSEC for Route 53, ZSK signatures are on the order of 10 
hours:

hilander.com<http://hilander.com>. 3599 IN RRSIG DNSKEY 13 2 3600 
2021021009 (
2021020923 38680 hilander.com<http://hilander.com>.
3H3QZt3qC2XbqkbumqsvRVeVrtgJVVRVGC/TZkc7vMuN
IdlL/wZrw+qBfYaSOex7dOp2PUP7pwW+NUgCXc2F7Q== )

A bunch of risks with this approach that needs to be mitigated, especially 
around static stability in the face of an issue with the ZSK signing process.  
But all solvable.  As part of this we also automated ZSK rotation (which 
happens less often, but still on the order of once a week).

Speaking of which, the DNSKEY RRSIG lifetime should be 11 hours, not
10 hours. The current expiration doesn't allow for client caching plus
clock skew. E.g.:

23:59:59: Recursive resolver queries authoritative servers for
hilander.com<http://hilander.com> DNSKEY, gets back record set with TTL 3600, 
RRSIG
inception 15:00:00, expiration 01:00:00.
(00:00:00: Authoritative servers switch to new DNSKEY record set, TTL
3600, inception 23:00:00, expiration 09:00:00.)
00:59:58: Validating stub resolver queries recursive resolver for
hilander.com<http://hilander.com> DNSKEY. gets back cached record set with TTL 
1, RRSIG
inception 15:00:00, RRSIG expiration 01:00:00.

If the stub resolver's clock is 3 seconds fast -- 01:00:01 -- and it
doesn't make an extra allowance for expired records or clock skew, it
will treat the record set as bogus.

(All other records except for DNSKEY are live signed, with the RRSIG
expiration set 1 hour after the TTL.)

<https://forums.aws.amazon.com/thread.jspa?threadID=05=0>

On Feb 8, 2021, at 9:27 PM, Paul Vixie 
mailto:p...@redbarn.org>> wrote:

CAUTION: This email originated from outside of the organization. Do not click 
links or open attachments unless you can confirm the sender and know the 
content is safe.



On Mon, Feb 08, 2021 at 01:45:06AM -0500, Viktor Dukhovni wrote:

...
I do not recommend either X.509 certificate or RRSIG lifetimes quite
this long.  Shorter lifetimes IMHO promote better discipline.


for my own zones i think i'm using one year signatures and regenerating them
from "cron" once per week -- just to be safe. so, not better discipline unless
you deliberately _live_ on the edge, which i think is an unwise practice.

i expect i'll crib together some bourne shellack to check my whole signature
chains and warn me when there's less than 72 hours remaining in any validity
period. going into SERVFAIL like this is an operational risk i shouldn't take.
--
Matt Nordhoff

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Re: [dns-operations] anybody awake over at comcast.net?

2021-02-09 Thread Peterson (AWS), Alec via dns-operations 
--- Begin Message ---
+1 for short RRSIG times and the discipline it enforces.  We went down this 
path when building DNSSEC for Route 53, ZSK signatures are on the order of 10 
hours:

hilander.com. 3599 IN RRSIG DNSKEY 13 2 3600 
2021021009 (
2021020923 38680 hilander.com.
3H3QZt3qC2XbqkbumqsvRVeVrtgJVVRVGC/TZkc7vMuN
IdlL/wZrw+qBfYaSOex7dOp2PUP7pwW+NUgCXc2F7Q== )

A bunch of risks with this approach that needs to be mitigated, especially 
around static stability in the face of an issue with the ZSK signing process.  
But all solvable.  As part of this we also automated ZSK rotation (which 
happens less often, but still on the order of once a week).

On Feb 8, 2021, at 9:27 PM, Paul Vixie 
mailto:p...@redbarn.org>> wrote:

CAUTION: This email originated from outside of the organization. Do not click 
links or open attachments unless you can confirm the sender and know the 
content is safe.



On Mon, Feb 08, 2021 at 01:45:06AM -0500, Viktor Dukhovni wrote:
...
I do not recommend either X.509 certificate or RRSIG lifetimes quite
this long.  Shorter lifetimes IMHO promote better discipline.

for my own zones i think i'm using one year signatures and regenerating them
from "cron" once per week -- just to be safe. so, not better discipline unless
you deliberately _live_ on the edge, which i think is an unwise practice.

i expect i'll crib together some bourne shellack to check my whole signature
chains and warn me when there's less than 72 hours remaining in any validity
period. going into SERVFAIL like this is an operational risk i shouldn't take.

--
Paul Vixie
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Re: [dns-operations] anybody awake over at comcast.net?

2021-02-09 Thread Peterson (AWS), Alec via dns-operations 
--- Begin Message ---
+1 for short RRSIG times and the discipline it enforces.  We went down this 
path when building DNSSEC for Route 53, ZSK signatures are on the order of 10 
hours:

hilander.com. 3599 IN RRSIG DNSKEY 13 2 3600 
2021021009 (
2021020923 38680 hilander.com.
3H3QZt3qC2XbqkbumqsvRVeVrtgJVVRVGC/TZkc7vMuN
IdlL/wZrw+qBfYaSOex7dOp2PUP7pwW+NUgCXc2F7Q== )

A bunch of risks with this approach that needs to be mitigated, especially 
around static stability in the face of an issue with the ZSK signing process.  
But all solvable.  As part of this we also automated ZSK rotation (which 
happens less often, but still on the order of once a week).

On Feb 8, 2021, at 9:27 PM, Paul Vixie 
mailto:p...@redbarn.org>> wrote:

CAUTION: This email originated from outside of the organization. Do not click 
links or open attachments unless you can confirm the sender and know the 
content is safe.



On Mon, Feb 08, 2021 at 01:45:06AM -0500, Viktor Dukhovni wrote:
...
I do not recommend either X.509 certificate or RRSIG lifetimes quite
this long.  Shorter lifetimes IMHO promote better discipline.

for my own zones i think i'm using one year signatures and regenerating them
from "cron" once per week -- just to be safe. so, not better discipline unless
you deliberately _live_ on the edge, which i think is an unwise practice.

i expect i'll crib together some bourne shellack to check my whole signature
chains and warn me when there's less than 72 hours remaining in any validity
period. going into SERVFAIL like this is an operational risk i shouldn't take.

--
Paul Vixie
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