disable dnssec for particular domain

Tony Finch dot at dotat.at
Wed Feb 7 12:26:06 UTC 2018


Pruned debug logs...

validating testa.eu/DS: looking for closest encloser
validating testa.eu/DS: NSEC3 QBQ65Q6097OCPPR0EUCQNSC1FHE073UA indicates potential closest encloser: 'eu'
validating testa.eu/DS: NSEC3 QBQ65Q6097OCPPR0EUCQNSC1FHE073UA at super-domain eu
validating testa.eu/DS: NSEC3 GLIBHU0LF7IH1TGCCS68E3R5508AKBFR proves name does not exist: 'testa.eu'
validating testa.eu/DS: NSEC3 GLIBHU0LF7IH1TGCCS68E3R5508AKBFR indicates optout
validating testa.eu/DS: NSEC3 4EIKQ8ORL4U4NTG72QEDRA6P3NDA1UNC proves name does not exist: '*.eu'
validating testa.eu/DS: in checkwildcard: *.eu
validating testa.eu/DS: NEEDNODATA = 0
validating testa.eu/DS: FOUNDNODATA = 0
validating testa.eu/DS: FOUNDOPTOUT = 1
validating testa.eu/DS: NEEDNOQNAME = 1
validating testa.eu/DS: FOUNDNOQNAME = 1
validating testa.eu/DS: NEEDNOWILDCARD = 1
validating testa.eu/DS: FOUNDNOWILDCARD = 1
validating testa.eu/DS: FOUNDCLOSEST = 1
validating testa.eu/DS: nonexistence proof(s) found

Looks OK so far...

fctx 0x7f1a5bfc1a10(testa.eu/DS): nonexistence validation OK
validating testa.eu/SOA: in dsfetched2: ncache nxdomain
validating testa.eu/SOA: resuming proveunsecure
validating testa.eu/SOA: insecurity proof failed

Then it goes pear-shaped.

Aha! I think what's happening here is that BIND is expecting a NODATA
response, to indicate that there is a delegation without a DS record.
(For an example, `dig +dnssec +multiline europa.eu ds)

However the validator gets an NXDOMAIN response claiming the domain
doesn't exist at all. But this is an opt-out NXDOMAIN so it is not a
proof. Nevertheless the validator believes it, and is convinced that it
has not proved the NODATA that it was expecting to prove, so it tells
itself it has not found an insecure delegation.

This is a tricky case. You can argue convincingly either way whether it is
a bug or not, I think. Even if it is a bug, fixing it is not going to
solve your problem any time soon - you need a pragmatic operational
solution.

What you should do is add some nameservers to the registration (serving an
empty zone or something), so that the .eu nameservers return a NODATA
response instead of an NXDOMAIN response. Then your private zone will
work.

Tony.
-- 
f.anthony.n.finch  <dot at dotat.at>  http://dotat.at/  -  I xn--zr8h punycode
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