Update on stats 2020-04

Viktor Dukhovni ietf-dane at dukhovni.org
Fri May 1 08:27:05 CEST 2020


News:  1. The most significant development this month is from Google managed
          DNS.  Since early April they appear to be signing all newly
          registered domains in a number of TLDs, including the top 3 most
          popular gTLDs: .com, .org and .net.  This amounts to ~10k domains per
          day, and has led to significantly faster growth in the DNS domain
          counts for the affected TLDs.  As a result the number of DNSSEC
          tracked by the DANE survey is now over 11.2 million.  Some graphs
          showing the change:

            https://stats.dnssec-tools.org/tld-graphs/com.png
            https://stats.dnssec-tools.org/tld-graphs/org.png
            https://stats.dnssec-tools.org/tld-graphs/net.png
            https://stats.dnssec-tools.org/tld-graphs/info.png
            https://stats.dnssec-tools.org/tld-graphs/biz.png

          and perhaps most dramatically:

            https://stats.dnssec-tools.org/tld-graphs/page.png
            https://stats.dnssec-tools.org/tld-graphs/ca.png

          Congratulations and thanks to Google.

       2. Also thanks to mijnhostingpartner.nl (a.k.a. mijnpartnergroep.nl)
          for resolving all outstanding DNSSEC denial of existence issues.
          Together with partial progress at registrar-servers.com the problem
          domain count is down ~50%.

          In short, much good news on the DNSSEC front this month.

Summary:  The DANE domain count is now 1,882,215

          The number of domains that return DNSSEC-validated replies in
          response to MX queries is 11,181,237.  Thus DANE TLSA is
          deployed on ~16.83% of domains with DNSSEC.

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 gTLD data via CZDS, and to
	  the TLD registries for .CH, .COM, .DK, .FR, .INFO, .IS, .LI,
	  .NL, .NU, .ORG and .SE.  More data sources of ccTLD
	  signed delegations welcome.

As of today I count 1,882,215 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 20 MX host providers by domain count are below.

  1028955 one.com
   137999 transip.nl
   100755 domeneshop.no
    88978 loopia.se
    74971 infomaniak.ch
    38612 active24.com
    31256 antagonist.nl
    30954 vevida.com
    28148 zxcs.nl
    26886 web4u.cz
    25101 udmedia.de
    24999 webreus.nl
    17442 bhosted.nl
    15059 flexfilter.nl
    13889 onebit.cz
    10334 protonmail.ch
     5791 netzone.ch
     5632 soverin.net
     5610 previder.nl
     5435 zonemx.eu

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 20 countries (each unique IP address is
counted, so multi-homed MX hosts are perhaps somewhat over-represented).

  6520 TOTAL
  2142 DE, Germany
  1306 US, United States
   955 NL, Netherlands
   567 FR, France
   267 GB, United Kingdom
   226 CZ, Czechia
   150 CA, Canada
    89 SG, Singapore
    89 CH, Switzerland
    81 SE, Sweden
    70 DK, Denmark
    47 IE, Ireland
    46 AU, Australia
    45 AT, Austria
    32 IN, India
    31 BR, Brazil
    28 RU, Russia
    28 FI, Finland
    27 PL, Poland
    26 JP, Japan

IPv6 is less common than IPv4 for MX hosts, and the top 20 countries by
DANE MX host IPv6 GeoIP are:

  3298 TOTAL
  1366 DE, Germany
   557 US, United States
   490 NL, Netherlands
   261 FR, France
   115 CZ, Czechia
   105 GB, United Kingdom
    43 SE, Sweden
    40 CA, Canada
    39 CH, Switzerland
    35 SG, Singapore
    29 AT, Austria
    22 RU, Russia
    16 DK, Denmark
    15 JP, Japan
    15 ID, Indonesia
    15 AU, Australia
    13 NO, Norway
    11 IE, Ireland
    11 FI, Finland
    11 BR, Brazil

There are 5532 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 organizations deploying DANE SMTP.

The number of published MX host TLSA RRsets found is 7682.  These cover 8602
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 341 (this is my ad-hoc criterion for a domain being a
large-enough actively used email domain).  Of these, 174 are in recent (last 90
days of) reports:

  12gobiking.nl           ingthink.com           ru.nl
  ac-strasbourg.fr        intermax.nl            ruhr-uni-bochum.de
  active24.cz             isc.org                rvo.nl
  aegee.org               itesco.cz              samba.org
  asf.com.pt              jpberlin.de            schoudercom.nl
  atelkamera.nu           kabelmail.de           schuurman-schoenen.nl
  atlas.cz                kadernickyservis.sk    skatteverket.se
  bayern.de               kingsquare.nl          smtp.cz
  belastingdienst.nl      klubpevnehozdravi.cz   societe.com
  bhosted.nl              kpn.com                solvinity.com
  bluerail.nl             krypton.cz             ssonet.nl
  boekwinkeltjes.nl       lazarus-ide.org        star.dk
  boozyshop.nl            leszexpertsfle.com     stil.dk
  boplatssyd-automail.se  litebit.eu             t-2.com
  bund.de                 loopia.se              t-2.net
  centrum.cz              lrz.de                 telfort.com
  clubedominante.com      lugeja.ee              thalesgroup.com
  comcast.net             mail.com               theletter.se
  comeseetv.com           mail.de                tilburguniversity.edu
  compagnie-des-sens.fr   mailbox.org            torproject.org
  coosto.com              mailplus.nl            transip.net
  corpoflow.nl            mailserver4.de         trashmail.com
  cuni.cz                 mammoetmail.com        triodos.be
  debian.org              mensa.de               triodos.co.uk
  dictu.nl                minbzk.nl              triodos.com
  digid.nl                mindef.nl              triodos.es
  dk-hostmaster.dk        minmyndighetspost.se   triodos.nl
  dns-oarc.net            mkbbelangen.nl         truetickets.nl
  domeneshop.no           mm1.nl                 tu-chemnitz.de
  egmontpublishing.dk     mpssec.net             tum.de
  elster.de               netbsd.org             uib.no
  emta.ee                 netic.dk               uitgeverijpica.nl
  ezorg.nl                nic.br                 uni-c.dk
  fau.de                  one.com                uni-erlangen.de
  fmc-na.com              onebit.cz              uni-muenchen.de
  freebsd.org             open.ch                unitybox.de
  freenet.de              openssl.org            unitymedia.de
  gentoo.org              optimail.cz            univie.ac.at
  gerryweber.nl           orverkiezing.com       utwente.nl
  gmx.at                  ouderportaal.nl        uv.es
  gmx.ch                  overheid.nl            uvt.nl
  gmx.com                 ozlabs.org             virusfree.cz
  gmx.de                  pathe.nl               volny.cz
  gmx.net                 personligalmanacka.se  web.de
  goget.nu                politie.nl             web200.eu
  govtrack.us             posteo.de              web200.hu
  habr.com                previder.nl            webcruitermail.no
  habramail.net           primexbt.com           westlotto.de
  handelsbanken.no        procurios.net          whatpulse.org
  handelsbanken.se        protonmail.ch          xfinity.com
  hierinloggen.nl         protonmail.com         xfinityhomesecurity.com
  hostpoint.ch            rediris.es             xfinitymobile.com
  hotelsinduitsland.com   registro.br            xs4all.net
  hr-manager.net          rijksoverheid.nl       xs4all.nl
  ietf.org                riseup.net             xworks.net
  inexio.net              rmit.ee                zone.eu
  infomaniak.ch           rotterdam.nl           zonevs.eu
  infomaniak.com          ru.ac.za               zorgmail.nl

Of the ~1.88 million domains, 4562 have "partial" TLSA records, that
cover only a subset of the (secondary) 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 590.  Some of these have additional MX hosts that don't have broken
TLSA records, so mail can still arrive via the remaining MX hosts.

To avoid email outages, 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
    https://github.com/internetstandards/toolbox-wiki/blob/master/DANE-for-SMTP-how-to.md
    https://mail.sys4.de/pipermail/dane-users/2018-February/000440.html
    https://community.letsencrypt.org/t/please-avoid-3-0-1-and-3-0-2-dane-tlsa-records-with-le-certificates/7022/17
    https://mail.sys4.de/pipermail/dane-users/2017-August/000417.html
    https://github.com/baknu/DANE-for-SMTP/wiki/2.-Implementation-resources

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

After eliminating parked domains that do not accept email, the number of
"real" email domains with bad DNSSEC support stands at 1128.  The top 13
name server operators with problem domains are:

    316 registrar-servers.com   (significant reduction from last month)
     72 movenext.nl
     70 ebola.cz
     69 axc.nl
     43 cdmon.net
     33 flevohost.nl
     30 tiscomhosting.nl
     28 hostnet.nl
     22 infracom.nl
     20 nrdns.nl
     18 is.nl
     16 metaregistrar.nl
     14 eatserver.nl

If anyone has good contacts at some 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.

Nine of the domains all whose nameservers have broken denial of existence
appear in the last 120 days of Google transparency reports:

  coren-sp.gov.br
  trt01.gov.br
  trtrio.gov.br
  trt1.jus.br
  trtrj.jus.br
  bncr.fi.cr
  ofda.gov[2]
  mobily.com.sa
  sauditelecom.com.sa

-- 
      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.

[2] For ofda.gov, TLSA lookups return truncated answers over UDP when
the EDNS buffer size is < 1555 bytes (e.g. to try and avoid UDP
fragmentation).  But the nameservers don't support TCP, so queries
timeout unless the EDNS buffer size is sufficiently large.


More information about the dane-users mailing list