Update on stats 2018-02

[Viktor Dukhovni]

Summary:  The total domain count is largely unchanged at 176970

	  The number DNSSEC domains in the survey stands at 5188779,
	  thus DANE TLSA is deployed on 3.41% of domains with DNSSEC.
	  Many DNSSEC domains use third-party MX hosts, that don't
	  have DNSSEC, so they can't benefit from DANE until their
	  providers secure the MX hosts.  Please ask your provider
	  to enable DNSSEC and DANE on their MX hosts.  [ It would
	  be especially significant if "redirect.ovh.net" were to
	  implement DNSSEC+DANE.  If someone personally knows the
	  right people to gently nudge at ovh.net, please do. ]

As of today I count 176970 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 handful of
DNS/hosting providers who've enabled DANE support in bulk for the
domains they host.  The top 10 MX host providers by domain count
are:

   68354 domeneshop.no
   63810 transip.nl
   18587 udmedia.de
    6202 bhosted.nl
    1749 nederhost.nl
    1231 yourdomainprovider.net
     742 ec-elements.com
     543 surfmailfilter.nl
     517 core-networks.de
     411 omc-mail.com

The real numbers are surely larger, because I don't have access to
the full zone data for most ccTLDs, especially .no/.nl/.de.  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):

   1286 DE, Germany
    843 US, United States
    464 NL, Netherlands
    337 FR, France
    190 GB, United Kingdom
    112 CZ, Czech Republic
     85 CA, Canada
     60 CH, Switzerland
     59 SE, Sweden
     56 BR, Brazil

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

    698 DE, Germany
    382 US, United States
    249 NL, Netherlands
    190 FR, France
     99 GB, United Kingdom
     61 CZ, Czech Republic
     35 SE, Sweden
     27 SG, Singapore
     25 CH, Switzerland
     13 SI, Slovenia

There are 3220 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 5219.  These
cover 5127 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 126 (this is my ad-hoc criterion for
a domain being a large-enough actively used email domain).  Of
these, 72 are in recent reports:

   gmx.at                   posteo.de               overheid.nl
   travelbirdbelgique.be    ruhr-uni-bochum.de      pathe.nl
   nic.br                   tum.de                  uvt.nl
   registro.br              uni-erlangen.de         xs4all.nl
   gmx.ch                   unitybox.de             domeneshop.no
   open.ch                  unitymedia.de           handelsbanken.no
   anubisnetworks.com       web.de                  webcruitermail.no
   gmx.com                  dk-hostmaster.dk        aegee.org
   isavedialogue.com        egmontpublishing.dk     debian.org
   mail.com                 netic.dk                freebsd.org
   solvinity.com            tilburguniversity.edu   gentoo.org
   trashmail.com            insee.fr                ietf.org
   xfinity.com              octopuce.fr             isc.org
   xfinityhomesecurity.com  comcast.net             netbsd.org
   xfinitymobile.com        dd24.net                openssl.org
   bayern.de                dns-oarc.net            samba.org
   bund.de                  gmx.net                 torproject.org
   elster.de                hr-manager.net          asf.com.pt
   fau.de                   mpssec.net              handelsbanken.se
   freenet.de               t-2.net                 minmyndighetspost.se
   gmx.de                   xs4all.net              skatteverket.se
   jpberlin.de              bhosted.nl              t-2.si
   lrz.de                   boozyshop.nl            mail.co.uk
   mail.de                  ouderportaal.nl         govtrack.us

Of the ~177000 domains, 1000 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 144. Below is the list of underlying MX hosts that serve
these domains and whose TLSA records don't match reality:

   Hall of Shame:

   white.agoracon.at             mail.seslost.cz               mx.datenknoten.me
   mail.dipietro.id.au           mail.zionbit.cz               rootbox.me
   eclipse.id.au                 mail.3c7.de                   mail.castleturing.net
   mx.krb.srv.pique.net.au       mail.absynth.de               mail.culm.net
   zebulon.pique.net.au          mail.all4.de                  anubis.delphij.net
   eufront.stansoft.bg           mail.awesome-it.de            mail.diejanssens.net
   eumembers.stansoft.bg         vm-1.eveng.de                 mail.efflam.net
   andbraiz.com                  mail.jo8.de                   smtp.bl.lybre.net
   mail.digitalwebpros.com       mx2.mindrun.de                mail.fscker.nl
   smtp-1.httrack.com            www.mtg.de                    smtp1.lococensus.nl
   mail.i-bible.com              mx2.pfp.de                    smtp2.lococensus.nl
   smtp.klam.com                 mail.scrz44.de                mail.myzt.nl
   demo.liveconfig.com           mail.secufon.de               bounder.steelyard.nl
   intranet.nctechcenter.com     mail.secure-chat.de           webmail.vivisol.nl
   ma.qbitnet.com                mx10.timotoups.de             mail.abanto-zierbena.org
   diablo.sgt.com                mail.diplomatic.email         eumembers.datacentrix.org
   tusk.sgt.com                  anotherone.braceyourself.es   genius.konundrum.org
   stmics01.smia-automotive.com  mail.0pc.eu                   smtp-01.tabalen.org
   stmics02.smia-automotive.com  gamepixel.eu                  mail.bacrau.ro
   romulus.wittsend.com          mail2.subse.eu                mail.itconnect.ro
   mail.zx.com                   servmail.fr                   mx.itconnect.ro
   mail.allq.cz                  mail.victorycity.com.hk       mail.pasion.ro
   mx2.aquasoft.cz               mail.demongeot.info           mail.familie-sander.rocks
   mx.bels.cz                    mail.nonoserver.info          mx1.shevaldin.ru
   mail.davidbodnar.cz           mx1.email.youwerehere.info    mail.labbrack.se
   owl.net-art.cz                mx2.email.youwerehere.info    mail1.puggan.se
   gaia.nfx.cz                   masrv.dedyn.io                mail.rostit.se
   petg.cz                       mail.rapidfuse.io             mail.amail.si

Please make sure to monitor the validity of your TLSA records, and
implement a reliable key rotation procedure.  Let's Encrypt users
in particular tend to forget that by default Let's Encrypt certificate
renewal replaces both the key and certificate, please read:

    https://mail.sys4.de/pipermail/dane-users/2018-February/000440.html
    http://postfix.1071664.n5.nabble.com/WoSign-StartCom-CA-in-the-news-td86436.html#a86444
    https://www.ietf.org/mail-archive/web/uta/current/msg01498.html
    https://community.letsencrypt.org/t/new-certbot-client-and-csr-option/15766
    https://www.internetsociety.org/deploy360/blog/2016/03/lets-encrypt-certificates-for-mail-servers-and-dane-part-2-of-2/
    https://community.letsencrypt.org/t/please-avoid-3-0-1-and-3-0-2-dane-tlsa-records-with-le-certificates/7022
    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 of any
kind, the number of "real" email domains with bad DNSSEC support
stands at 112.  The top 8 (the rest have too few domains to include
in a top 10) name server operators with problem domains
are:

  21 firstfind.nl
   7 active24.cz
   6 tse.jus.br
   5 metaregistrar.nl
   4 ignum.com
   4 glbns.com
   4 army.mil
   4 1cocomo.com

All DNS-broken domains that appear in historical Google Email
transparency reports have at least one working nameserver.

-- 
	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.