Update on stats 2018-08

[Viktor Dukhovni]

Credits:  The coverage of DNSSEC domains continues to improve with
	  ongoing data support from Paul Vixie of Farsight Security.
	  Credits also due to ICANN for the gTLD data via CZDS,
	  Afilias for access to .INFO zone data, data contributions
	  from the TLD registries for .CH, .DK, .INFO, .LI, .NL and
	  .ORG and open access for .FR, .NU and .SE.  More data
	  sources of ccTLD signed delegations welcome.

Summary:  The DANE domain count is now 314,472

	  The number DNSSEC domains in the survey stands at 8,908,099.
	  Thus DANE TLSA is deployed on 3.52% of domains with DNSSEC.

	  All DNSSEC denial of existence issues are resolved at
	  mijnhostingparner.nl and tse.jus.br.

As of today I count 314,472 domains with correct SMTP DANE TLSA
records at every primary MX host that accepts connections[1].  As
expected the bulk of the DANE domains are hosted by the DNS/email
hosting providers who've enabled DANE support for the customer
domains they host.  The top 15 MX host providers by domain count are:

   112848 transip.nl
    96132 domeneshop.no
    34452 active24.com
    23638 udmedia.de
    10651 bhosted.nl
     3720 interconnect.nl
     2491 provalue.nl
     2456 nederhost.nl
     1666 yourdomainprovider.net
     1297 xcellerate.nl
     1177 hi7.de
     1093 surfmailfilter.nl
      724 omc-mail.com
      608 core-networks.de
      567 mailbox.org

The real numbers are surely larger, because I don't have access to
the full zone data for most ccTLDs, especially .no/.cz/.de/.eu/.be.
Speaking of countries, the IPv4 GeoIP distribution of DANE-enabled
MX hosts shows the below top 10 countries (each unique IP address
is counted, so multi-homed MX hosts are perhaps somewhat
over-represented):

  4263     TOTAL
  1453 DE, Germany
   922 US, United States
   541 NL, Netherlands
   346 FR, France
   161 GB, United Kingdom
   124 CZ, Czech Republic
   100 CA, Canada
    58 SE, Sweden
    57 SG, Singapore
    56 CH, Switzerland

IPv6 is still comparatively rare for MX hosts, and the top 10
countries by DANE MX host IPv6 GeoIP are (same top 6).

  2066     TOTAL
   813 DE, Germany
   435 US, United States
   309 NL, Netherlands
   194 FR, France
    66 GB, United Kingdom
    66 CZ, Czech Republic
    37 SE, Sweden
    28 SG, Singapore
    21 CH, Switzerland
    18 AT, Austria

There are 3563 unique zones in which the underlying MX hosts are
found, this counts each of the above providers as just one zone,
so is a measure of the breadth of adoption in terms of servers
deployed.

The number of published MX host TLSA RRsets found is 5015.  These
cover 5376 distinct MX hosts (some MX hosts share the same TLSA
records through CNAMEs).

The number of domains that at some point were listed in Gmail's
email transparency report is 165 (this is my ad-hoc criterion for
a domain being a large-enough actively used email domain).  Of
these, 91 are in recent reports:

  gmx.at                   jpberlin.de              ouderportaal.nl
  transip.be               lrz.de                   overheid.nl
  nic.br                   mail.de                  pathe.nl
  registro.br              posteo.de                politie.nl
  gmx.ch                   ruhr-uni-bochum.de       transip.nl
  open.ch                  tum.de                   truetickets.nl
  anubisnetworks.com       uni-erlangen.de          utwente.nl
  fmc-na.com               unitybox.de              uvt.nl
  gmx.com                  unitymedia.de            xs4all.nl
  mail.com                 web.de                   domeneshop.no
  societe.com              dk-hostmaster.dk         rushtrondheim.no
  solvinity.com            egmontpublishing.dk      webcruitermail.no
  t-2.com                  netic.dk                 aegee.org
  trashmail.com            tilburguniversity.edu    debian.org
  xfinity.com              insee.fr                 freebsd.org
  xfinityhomesecurity.com  octopuce.fr              gentoo.org
  xfinitymobile.com        comcast.net              ietf.org
  active24.cz              dd24.net                 isc.org
  cuni.cz                  gmx.net                  netbsd.org
  destroystores.cz         hr-manager.net           openssl.org
  klubpevnehozdravi.cz     inexio.net               samba.org
  knizni-magazin.cz        mpssec.net               torproject.org
  nic.cz                   t-2.net                  asf.com.pt
  optimail.cz              transip.net              handelsbanken.se
  smtp.cz                  xs4all.net               iis.se
  bayern.de                bhosted.nl               minmyndighetspost.se
  bund.de                  boozyshop.nl             skatteverket.se
  elster.de                deltion.nl               t-2.si
  fau.de                   hierinloggen.nl          govtrack.us
  freenet.de               interconnect.nl
  gmx.de                   intermax.nl

Of the ~314000 domains, 1193 have "partial" TLSA records, that
cover only a subset of the MX hosts.  While this protects traffic
to some of the MX hosts, such domains are still vulnerable to the
usual active attacks via the remaining MX hosts.

The number of domains with incorrect TLSA records or failure to
advertise STARTTLS (even though TLSA records are published) stands
today at 287. Some of these have additional MX hosts that don't
have broken TLSA records, so mail can still arrive via the remaining
MX hosts.  A partial list is available at:

  https://github.com/danefail/list

To avoid getting listed, please make sure to monitor the validity
of your own TLSA records, and implement a reliable key rotation
procedure.  See:

    https://dane.sys4.de/common_mistakes
    http://imrryr.org/~viktor/ICANN61-viktor.pdf
    http://imrryr.org/~viktor/icann61-viktor.mp3

    http://tools.ietf.org/html/rfc7671#section-8.1
    http://tools.ietf.org/html/rfc7671#section-8.4

The DNSSEC denial of existence breakage is lower this month, as a
result of a complete resolution of all issues at mijnhostingpartner.nl
and tse.jus.br.  After eliminating parked domains that do not accept
email of any kind, the number of "real" email domains with bad
DNSSEC support stands at 708.  The top 20 name server operators
with problem domains are:

   112 webspacecontrol.com	(reportedly working on a solution)
    64 is.nl
    51 dotserv.com
    39 tiscomhosting.nl
    33 sylconia.net
    33 metaregistrar.nl
    29 nrdns.nl
    25 active24.cz		(some broken wildcard cnames)
    21 host-redirect.com
    15 nazwa.pl			(some broken wildcard NS RRs)
    13 psb1.org
    12 ultratek.com
    11 blauwblaatje.nl
    11 army.mil
     9 dnscluster.nl
     8 vultr.com
     8 pcextreme.nl
     8 glbns.com
     7 forpsi.net
     6 domdom.hu

If anyone has good contacts at one of these providers, please
encourage them to remediate not only the broken domains (I can send
them a list), but also the root cause that makes the breakage
possible.

None of the domains all whose nameservers have broken denial of
existence appear in historical Google reports.

-- 
        Viktor.

[1] Some domains deliberately include MX hosts that are always
down, presumably as a hurdle to botnet SMTP code that gives up
where real MTAs might persist.  I am not a fan of this type of
defence (it can also impose undue latency on legitimate email).
However, provided the dead hosts still have TLSA records, (which
don't need to match anything, just need to exist and be well-formed)
there's no loss of security.