draft-reddy-add-enterprise-split-dns-03.xml

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<rfc category="std" docName="draft-reddy-add-enterprise-split-dns-03"
     ipr="trust200902">
  <front>
    <title abbrev="Split-Horizon DNS Configuration">Split-Horizon DNS
    Configuration in Enterprise Networks</title>

    <author fullname="Tirumaleswar Reddy" initials="T." surname="Reddy">
      <organization abbrev="McAfee">McAfee, Inc.</organization>

      <address>
        <postal>
          <street>Embassy Golf Link Business Park</street>

          <city>Bangalore</city>

          <region>Karnataka</region>

          <code>560071</code>

          <country>India</country>
        </postal>

        <email>kondtir@gmail.com</email>
      </address>
    </author>

    <author fullname="Dan Wing" initials="D." surname="Wing">
      <organization abbrev="Citrix">Citrix Systems, Inc.</organization>

      <address>
        <postal>
          <street>4988 Great America Pkwy</street>

          <city>Santa Clara</city>

          <region>CA</region>

          <code>95054</code>

          <country>USA</country>
        </postal>

        <email>danwing@gmail.com</email>
      </address>
    </author>

    <author fullname="Kevin Smith" initials="K." surname="Smith">
      <organization abbrev="Vodafone">Vodafone Group</organization>

      <address>
        <postal>
          <street>One Kingdom Street</street>

          <city>London</city>

          <country>UK</country>
        </postal>

        <email>kevin.smith@vodafone.com</email>
      </address>
    </author>

    <date />

    <workgroup>ADD</workgroup>

    <abstract>
      <t>When split-horizon DNS is deployed by a network, certain domains are
      only resolvable by querying the network-designated DNS server. DNS
      clients which use DNS servers not provided by the network need to route
      those DNS domain queries to the network-designated DNS server. This
      document informs DNS clients of split-horizon DNS, their DNS domains,
      and is compatible with encrypted DNS.</t>
    </abstract>
  </front>

  <middle>
    <section anchor="intro" title="Introduction">
      <t>Historically, an endpoint would utilize network-designated DNS
      servers upon joining a network (e.g., DHCP OFFER, IPv6 Router
      Advertisement). While it has long been possible to configure endpoints
      to ignore the network's suggestions and use a (public) DNS server on the
      Internet, this was seldom used because some networks block UDP/53 (in
      order to enforce their own DNS policies). Also, there has been an
      increase in the availability of "public resolvers" <xref
      target="RFC8499"></xref> which DNS clients may be pre-configured to use
      instead of the default network resolver for a variety of reasons (e.g.,
      offer a good reachability, support an encrypted transport, provide a
      claimed privacy policy, (lack of) filtering). With the advent of DoT and
      DoH, such network blocking is more difficult, but the endpoint is unable
      to (properly) resolve split-horizon DNS domains which must query the
      network-designated DNS server.</t>

      <t>This document specifies a mechanism to indicate which DNS zones are
      used for split-horizon DNS. DNS clients can discover and authenticate
      DNS servers provided by the network, for example using the techniques
      proposed in <xref target="I-D.ietf-add-dnr"></xref> and <xref
      target="I-D.ietf-add-ddr"></xref>. Discovery of encrypted DNS server for
      roaming enterprise endpoints is discussed in <xref
      target="I-D.btw-add-ipsecme-ike"></xref> (see <xref
      target="VPN"></xref>). </t>

      <t>Provisioning Domains (PvDs) are defined in <xref
      target="RFC7556"></xref> as sets of network configuration information
      that clients can use to access networks, including rules for DNS
      resolution and proxy configuration. <xref target="RFC8801"></xref>
      defines a mechanism for discovering multiple Explicit PvDs on a single
      network and their Additional Information by means of an HTTP-over-TLS
      query using a URI derived from the PvD ID. This set of additional
      configuration information is referred to as a Web Provisioning Domain
      (Web PvD).</t>

      <t>This document defines two PvD Key:<list style="hanging">
          <t hangText="The NetworkDNSOnly PvD Key:">which determines if
          network will block, or attempt to block, DNS queries sent to DNS
          servers that were not signaled by the network.</t>

          <t hangText="The ErrorNetworkDNSOnly PvD Key:">which contains a
          human-friendly description of the reason to block access to DNS
          servers that were not signaled by the network. </t>
        </list></t>
    </section>

    <section anchor="notation" title="Terminology">
      <t>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
      "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
      "OPTIONAL" in this document are to be interpreted as described in BCP 14
      <xref target="RFC2119"></xref><xref target="RFC8174"></xref> when, and
      only when, they appear in all capitals, as shown here.</t>

      <t>This document makes use of the terms defined in <xref
      target="RFC8499"></xref>. The terms "Private DNS", "Global DNS" and
      "Split DNS" are defined in <xref target="RFC8499"></xref>.</t>

      <t>'Encrypted DNS' refers to a DNS protocol that provides an encrypted
      channel between a DNS client and server (e.g., DoT, DoH, or DoQ).</t>

      <t>The term "enterprise network" in this document extends to a wide
      variety of deployment scenarios. For example, an "enterprise" can be a
      Small Office, Home Office or Corporation. The clients that connect to a
      enterprise network can securely authenticate that network and the client
      is sure that it has connected to the network it was expecting.</t>
    </section>

    <section anchor="split-horizon" title="Split DNS">
      <t><xref target="RFC2826"></xref> "does not preclude private networks
      from operating their own private name spaces" but notes that if private
      networks "wish to make use of names uniquely defined for the global
      Internet, they have to fetch that information from the global DNS naming
      hierarchy".</t>

      <t>There are various DNS deployments outside of the global DNS,
      including "split horizon" deployments and DNS usages on private (or
      virtual private) networks. In a split horizon, an authoritative server
      gives different responses to queries from the Internet than they do to
      network-designated DNS servers; while some deployments differentiate
      internal queries from public queries by the source IP address, the
      concerns in Section 3.1.1 of <xref target="RFC6950"></xref> relating to
      trusting source IP addresses apply to such deployments.</t>

      <t>When the internal address space range is private <xref
      target="RFC1918"></xref>, this makes it both easier for the server to
      discriminate public from private and harder for public entities to
      impersonate nodes in the private network. The use cases that motivate
      split-horizon DNS typically involve restricting access to some network
      services -- intranet resources such as internal web sites, development
      servers, or directories, for example -- while preserving the ease of use
      offered by domain names for internal users.</t>

      <t>A typical use case is an Enterprise network can require one or more
      DNS domains to be resolved via network-designated DNS servers. This can
      be a special domain, such as "corp.example.com" for an enterprise that
      is publicly known to use "example.com". In this case, the endpoint needs
      to be informed what the private domain names are and what the IP
      addresses of the network-designated DNS servers are. An Enterprise can
      also run a different version of its global domain on its internal
      network. In that case, the client is instructed to send DNS queries for
      the enterprise public domain (e.g., "example.com") to the
      network-designated DNS servers. A configuration for this deployment
      scenario is referred to as a Split DNS configuration. Another use case
      for split-horizon DNS is Cellular and Fixed-access networks (ISPs)
      typically offer private domains, including account status/controls, and
      free education initiatives <xref target="INS"></xref>.</t>

      <t>The PvD RA option defined in <xref target="RFC8801"></xref> SHOULD
      set the H-flag to indicate that Additional Information is available.
      This Additional Information JSON object SHOULD include the "dnsZones"
      key to define the DNS domains for which the network claims
      authority.</t>
    </section>

    <section anchor="dnsZones" title="PvD dnsZones">
      <t>As discussed in <xref target="split-horizon"></xref>, the Enterprise
      internal resources tend to have private DNS names. An enterprise can
      also run a different version of its global domain on its internal
      network, and require the use of network-designated DNS servers to get
      resolved.</t>

      <t>The PvD Key dnsZones is defined in <xref target="RFC8801"></xref>.
      The PvD Key dnsZones adds support for DNS domains for which the network
      claims authority. The private domains specified in the dnsZones key are
      intended to be resolved using network-designated DNS servers. The
      private domains in dnsZones are only reachable by devices authenticated
      or attached to the network. The global domains specified in the dnsZones
      key have a different version in the internal network. DNS resolution for
      other domains remains unchanged.</t>

      <t>The dnsZones PvD Key conveys the specified DNS domains that need to
      be resolved using an network-designated DNS server. The DNS root zone
      (".") MUST be ignored if it appears in dnsZones. Other generic or global
      domains, such as Top-Level Domains (TLDs), similarly MUST be ignored if
      they appear in dnsZones.</t>

      <t>For each dnsZones entry, the client can use the network-designated
      DNS servers to resolve the listed domains and its subdomains. Other
      domain names may be resolved using some other DNS servers that are
      configured independently. For example, if the dnsZones key specifies
      "example.test", then "example.test", "www.example.test", and
      "mail.eng.example.test" can be resolved using the network-designated DNS
      resolver(s), but "otherexample.test" and "ple.test" can be resolved
      using the system's public resolver(s).</t>

      <section title="Authority over the Domains">
        <t>To comply with <xref target="RFC2826"></xref> the split-horizon DNS
        zone must either not exist in the global DNS hierarchy or must be
        authoritatively delegated to the split-horizon DNS server to answer.
        The client can use the mechanism described in <xref
        target="I-D.ietf-add-dnr"></xref> to discover the network-designated
        resolvers. To determine if the network-designated encrypted resolvers
        are authoritative over the domains in DnsZones, the client performs
        the following steps for each domain in DnsZones:</t>

        <t><list style="numbers">
            <t>The client sends an NS query for the domain in DnsZones. This
            query MUST only be sent over encrypted DNS session to a public
            resolver that is configured independently or to a
            network-designated resolver whose response will be validated using
            DNSSEC as described in <xref target="RFC6698"></xref>.</t>

            <t>The client checks that the NS RRset matches, or is a subdomain
            of, any one of the ADN of the discovered network-designated
            encrypted DNS resolvers.<list style="letters">
                <t>If the match fails, the client determines the network is
                not authoritative for the indicated domain. It might log an
                error, reject the network entirely (because the network lied
                about its authority over a domain) or other action.</t>

                <t>If the match succeeds, the client can then establish a
                secure connection to that network-designated resolver and
                validate its certificate. <list style="symbols">
                    <t>If the server certificate does not validate and a
                    secure connection cannot be established to the network
                    designated resolver, the client can action as discussed in
                    step 3 (A).</t>

                    <t>If the server certificate validation is successful and
                    a secure connection is established, the client can
                    subsequently resolve the domains in that subtree using the
                    network-designated resolver.</t>
                  </list></t>
              </list></t>

            <t>As an exception to this rule, the client need not perform the
            above validation for domains reserved for special use <xref
            target="RFC6761"></xref> or <xref target="RFC6762"></xref> such as
            ".home.arpa" or ".local".</t>
          </list></t>

        <t>For example, if in an network the private domain names are defined
        under "internal.corp1.example.com". The DnsZones PvD Key would
        indicate that "*.internal.corp1.example.com" are private domain names.
        The client can trigger a NS query of "internal.corp1.example.com" and
        the NS RRset returns that the nameserver is "ns1.corp2.example.com".
        The client would then connect to the network-designated encrypted
        resolver whose name is "ns1.corp2.example.com", authenticate it using
        server certificate validation in TLS handshake, and use it for
        resolving the domains in the subtree of
        "*.internal.corp1.example.com".</t>
      </section>
    </section>

    <section anchor="SplitDNSAllowed"
             title="PvD NetworkDNSOnly and ErrorNetworkDNSOnly Keys">
      <t>Some enterprise networks require clients to query the
      network-designated DNS servers, it sets the PvD NetworkDNSOnly key to
      True, otherwise sets NetworkDNSOnly to False. If NetworkDNSOnly is set
      to True, it implies the network will block, or attempt to block, DNS
      queries sent to DNS servers that were not signaled by the network. If
      NetworkDNSOnly is True, the ErrorNetworkDNSOnly key MUST contain a
      human-friendly description for this block. This information is intended
      for human consumption (not automated parsing). The ErrorNetworkDNSOnly
      key is useful when the client does not use DNS lookup to reach the DNS
      servers not provided by the network. For example, the client can be
      pre-configured with both the domain name and IP addresses of the DNS
      server not provided by the network (Section 7.1 in <xref
      target="RFC8310"></xref>) or the client can be pre-configured with the
      IP address of the resolver, and it uses IP address in the certificate as
      identifier (see <xref target="RFC8738"></xref>). In this case, the
      extended error code "Blocked" defined in <xref target="RFC8914"></xref>
      cannot be returned to the client to provide additional information about
      the cause for the block.</t>

      <t>The NetworkDNSOnly set to True is an internal security policy
      expression by the operator of the network but is not a policy
      prescription to the endpoints to disable its use of its other configured
      DNS servers; that is, the endpoint can ignore NetworkDNSOnly set to
      True. If joining an un-trusted network (e.g., coffeeshop, hotel, airport
      network), a True value of NetworkDNSOnly MUST be ignored. The mechanism
      the client uses to determine 'trusted network' to assist the user MUST
      involve authenticated identity of the network (not merely matching SSID
      in the case of WiFi), such as 802.1X or confirming the
      network-designated encrypted resolver name is pre-configured in the
      Operating System and TLS handshake with it succeeds. For example, the
      client can determine "Open" (unencrypted) wireless networks are
      untrusted networks, notify the user that using a shared and public
      Pre-Shared Key (PSK) for wireless authentication is a untrusted network.
      If the pre-shared-key is the same for all clients that connect to the
      same WLAN, the shared key will be available to all nodes, including
      attackers, so it is possible to mount an active on-path attack (e.g.,
      <xref target="Evil-Twin"></xref>, <xref target="Krack"></xref>, <xref
      target="Dragonblood"></xref>). For example, coffee shops and air ports
      use PSK and are unwilling to perform complex configuration on their
      networks. In addition, customers are generally unwilling to do
      complicated provisioning on their devices just to obtain free Wi-Fi.
      This type of networks can be tagged as "untrusted networks" with minimal
      human intervention. In such cases the endpoint MAY choose to use an
      alternate network (e.g., cellular) to resolve the global domain
      names.</t>

      <section anchor="Scope" title="Scope of NetworkDNSOnly Key">
        <t>If a device is managed by an enterprise's IT department, the device
        can be configured to use a specific encrypted DNS server. This
        configuration may be manual or rely upon whatever deployed device
        management tool in an enterprise network. For example, customizing
        Firefox using Group Policy to use the Enterprise DoH server is
        discussed in <xref target="Firefox-Policy"></xref> for Windows and
        MacOS, and setting Chrome policies is discussed in <xref
        target="Chrome-Policy"></xref> and <xref
        target="Chrome-DoH"></xref>.</t>

        <t>If mobile device management (MDM) (e.g., <xref
        target="MDM-Apple"></xref>) secures a device, MDM can configure
        OS/browser with a specific encrypted DNS server. If an endpoint is
        on-boarded, for example, using Over-The-Air (OTA) enrollment <xref
        target="OTA"></xref> to provision the device with a certificate and
        configuration profile, the configuration profile can include the
        authentication domain name (ADN) of the encrypted DNS server. The
        OS/Browser can use the configuration profile to use a specific
        encrypted DNS server. In this case, MDM is not installed on the
        device.</t>

        <t>Provisioning IT-managed devices, BYOD devices with MDM or
        configuration profile with network-designated DNS server is outside
        the scope of this document.</t>

        <t>Typically, Enterprise networks do not assume that all devices in
        their network are managed by the IT team or MDM, especially in the
        quite common BYOD scenario. The endpoint can use the discovered
        network-designated DNS server to only access DNS names for which the
        Enterprise network claims authority and use another public DNS server
        for global domains or use the discovered network-designated DNS server
        to access both private domains and global domains.</t>

        <t>The scope of NetworkDNSOnly key is restricted to unmanaged BYOD
        devices without a configuration profile on explicitly trusted
        networks. In this use case, the user has authorized the client to
        override local DNS settings for a specific network. It is similar to
        the way users explicitly disable VPN connection in specific networks
        and VPN connection is enabled by default in other networks for
        privacy. The unmanaged BYOD devices use mutual authentication of the
        client and the enterprise network. The client is typically
        authenticated with their user credentials (e.g., username and
        password). The network is typically authenticated with a certificate
        (e.g., PEAP-MSCHAPv2 <xref target="PEAP"></xref>) or a
        mutually-authenticated key exchange which is well-defended from
        offline attacks (e.g., EAP-pwd <xref target="RFC8146"></xref>, EAP-PSK
        <xref target="RFC4764"></xref>). Importantly, WPA-PSK and WPA2-PSK are
        not well-defended from offline attacks and MUST NOT be used in
        conjunction with NetworkDNSOnly set to True.</t>

        <t><list style="hanging">
            <t hangText="Note: ">Many users have privacy and personal data
            sovereignty concerns with employers installing MDM on their
            personal devices; they are concerned that admin can glean personal
            information and could control how they use their devices. When
            users do not install MDM on their devices, IT admins do not get
            visibility into the security posture of those devices. To overcome
            this problem, a host agent can cryptographically attest the
            security status associated with device, such as minimum pass code
            length, biometric login enabled, OS version etc. This approach is
            fast gaining traction especially with the advent of closed OS like
            <xref target="win10s">Windows 10 in S mode</xref> or <xref
            target="Chromebook">Chromebook</xref>, where applications are
            sandboxed (e.g., ransomware attack is not possible) and
            applications can only be installed via the OS store.</t>
          </list></t>
      </section>
    </section>

    <section title="An Example">
      <t>The following example shows how the JSON keys defined in this
      document can be used:</t>

      <t><figure>
          <artwork><![CDATA[   {
     "identifier": "cafe.example.com.",
     "expires": "2020-05-23T06:00:00Z",
     "prefixes": ["2001:db8:1::/48", "2001:db8:4::/48"],
     "NetworkDNSOnly": True, 
      "dnsZones:": ["city.other.test", "example.com"]
   }]]></artwork>
        </figure></t>

      <t>The JSON keys "identifier", "expires", and "prefixes" are defined in
      <xref target="RFC8801"></xref>.</t>
    </section>

    <section anchor="VPN" title="Roaming Enterprise Users">
      <t>In this Enterprise scenario (Section 1.1.3 of <xref
      target="RFC7296"></xref>), a roaming user connects to the Enterprise
      network through an VPN tunnel (e.g., IPsec, SSL, Wireguard). The
      split-tunnel Virtual Private Network (VPN) configuration allows the
      endpoint to access hosts that reside in the Enterprise network <xref
      target="RFC8598"></xref> using that tunnel; other traffic not destined
      to the Enterprise does not traverse the tunnel. In contrast, a
      non-split- tunnel VPN configuration causes all traffic to traverse the
      tunnel into the Enterprise.</t>

      <t>When the VPN tunnel is IPsec, the encrypted server hosted by the
      Enterprise network can be securely discovered by the endpoint using the
      ENCDNS_IP*_* IKEv2 Configuration Payload Attribute Types defined in
      <xref target="I-D.btw-add-ipsecme-ike"></xref>. For split-tunnel VPN
      configurations, the endpoint uses the discovered encrypted DNS server to
      resolve domain names for which the Enterprise network claims authority.
      For non-split-tunnel VPN configurations, the endpoint uses the
      discovered encrypted DNS server to resolve both global and private
      domain names.</t>

      <t>Other VPN tunnel types have similar configuration capabilities, not
      detailed here.</t>
    </section>

    <section title="Upstream Encryption">
      <t>If an Enterprise network is using a local encrypted DNS server
      configured as a Forwarding DNS server <xref target="RFC8499"></xref>
      relying upon the upstream resolver (e.g., at an ISP) to perform
      recursive DNS lookups, DNS messages exchanged between the local
      encrypted DNS server and the recursive resolver MUST be encrypted.</t>

      <t>If the Enterprise network is using the local encrypted DNS server
      configured as a recursive DNS server, DNS messages exchanges between the
      recursive resolver and authoritative servers SHOULD be encrypted to
      conform to the requirements discussed in <xref
      target="I-D.ietf-dprive-phase2-requirements"></xref>.</t>
    </section>

    <section anchor="Security" title="Security Considerations">
      <t>Clients may want to preconfigure global domains for TLDs and
      Second-Level Domains (SLDs) to prevent malicious DNS redirections for
      well-known domains. This prevents users from unknowingly giving DNS
      queries to third parties. This is even more important if those
      well-known domains are not deploying DNSSEC, as the attached network
      could then even modify the DNS answers without detection. It is similar
      to the mechanism discussed in Section 8 of <xref
      target="RFC8598"></xref>.</t>

      <t>The content of dnsZones and NetworkDNSOnly may be passed to another
      (DNS) program for processing. As with any network input, the content
      SHOULD be considered untrusted and handled accordingly. </t>
    </section>

    <section anchor="IANA" title="IANA Considerations">
      <t>IANA is requested to add NetworkDNSOnly and ErrorSplitDNSBlocked PvD
      Keys to the Additional Information PvD Keys registry
      (https://www.iana.org/assignments/pvds/pvds.xhtml).</t>
    </section>

    <section title="Acknowledgements">
      <t>Thanks to Mohamed Boucadair, Jim Reid, Ben Schwartz, Tommy Pauly,
      Paul Vixie and Vinny Parla for the discussion and comments. The authors
      would like to give special thanks to Ben Schwartz for his help.</t>
    </section>
  </middle>

  <!--  *****BACK MATTER ***** -->

  <back>
    <references title="Normative References">
      <?rfc include='reference.RFC.2119'?>

      <?rfc include='reference.RFC.8174'?>

      <?rfc include='reference.RFC.8801'?>

      <?rfc include='reference.RFC.2826'?>

      <?rfc include='reference.RFC.1918'?>

      <?rfc include='reference.RFC.6761'?>

      <?rfc include='reference.RFC.6762'?>
    </references>

    <references title="Informative References">
      <?rfc include='reference.RFC.8499'?>

      <?rfc include='reference.RFC.8598'?>

      <?rfc include='reference.RFC.7296' ?>

      <?rfc include='reference.RFC.8146' ?>

      <?rfc include='reference.RFC.4764' ?>

      <?rfc include='reference.RFC.6950' ?>

      <?rfc include='reference.RFC.7556' ?>

      <?rfc include='reference.RFC.6698'?>

      <?rfc include='reference.RFC.8310'?>

      <?rfc include='reference.RFC.8914'?>

      <?rfc include='reference.RFC.8738'?>

      <?rfc include='reference.I-D.ietf-dprive-phase2-requirements'?>

      <?rfc include='reference.I-D.btw-add-ipsecme-ike'?>

      <?rfc include='reference.I-D.ietf-add-dnr'?>

      <?rfc include='reference.I-D.ietf-add-ddr'?>

      <!-- not yet in XML library           <?rfc include='reference.I-D.ietf-add-ddr'?> 
           <?rfc include='reference.I-D.ietf-add-dnr'?> -->

      <reference anchor="Firefox-Policy"
                 target="https://github.com/mozilla/policy-templates/blob/master/README.md#dnsoverhttps">
        <front>
          <title>Policy templates for Firefox</title>

          <author></author>

          <date day="" month="" year="" />
        </front>
      </reference>

      <reference anchor="Chrome-Policy"
                 target="https://support.google.com/chrome/a/answer/2657289?hl=en">
        <front>
          <title>Chrome policies for users or browsers</title>

          <author>
            <organization>The Unicode Consortium</organization>
          </author>

          <date day="" month="" year="" />
        </front>
      </reference>

      <reference anchor="Chrome-DoH"
                 target="https://www.chromium.org/developers/dns-over-https">
        <front>
          <title>Chrome DNS over HTTPS (aka DoH)</title>

          <author>
            <organization>The Unicode Consortium</organization>
          </author>

          <date day="" month="" year="" />
        </front>
      </reference>

      <reference anchor="win10s"
                 target="https://www.microsoft.com/en-us/windows/s-mode">
        <front>
          <title>Windows 10 in S mode</title>

          <author>
            <organization>Microsoft</organization>
          </author>

          <date day="" month="" year="" />
        </front>
      </reference>

      <reference anchor="Chromebook"
                 target="https://support.google.com/chromebook/answer/3438631?hl=en">
        <front>
          <title>Chromebook security</title>

          <author>
            <organization>Microsoft</organization>
          </author>

          <date day="" month="" year="" />
        </front>
      </reference>

      <reference anchor="MDM-Apple"
                 target="https://developer.apple.com/documentation/devicemanagement">
        <front>
          <title>Mobile Device Management</title>

          <author>
            <organization>Apple</organization>
          </author>

          <date day="" month="" year="" />
        </front>
      </reference>

      <reference anchor="OTA"
                 target="https://developer.apple.com/library/archive/documentation/NetworkingInternet/Conceptual/iPhoneOTAConfiguration/OTASecurity/OTASecurity.html">
        <front>
          <title>Over-the-Air Profile Delivery Concepts</title>

          <author>
            <organization>Apple</organization>
          </author>

          <date day="" month="" year="" />
        </front>
      </reference>

      <reference anchor="PEAP"
                 target="https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-peap/5308642b-90c9-4cc4-beec-fb367325c0f9">
        <front>
          <title>[MS-PEAP]: Protected Extensible Authentication Protocol
          (PEAP)</title>

          <author>
            <organization>Microsoft</organization>
          </author>

          <date day="" month="" year="" />
        </front>
      </reference>

      <reference anchor="Evil-Twin"
                 target="https://en.wikipedia.org/wiki/Evil_twin_(wireless_networks)">
        <front>
          <title>Evil twin (wireless networks)</title>

          <author>
            <organization>The Unicode Consortium</organization>
          </author>

          <date day="" month="" year="" />
        </front>
      </reference>

      <reference anchor="Krack" target="https://www.krackattacks.com/">
        <front>
          <title>Key Reinstallation Attacks</title>

          <author>
            <organization>The Unicode Consortium</organization>
          </author>

          <date day="" month="" year="2017" />
        </front>
      </reference>

      <reference anchor="Dragonblood"
                 target="https://papers.mathyvanhoef.com/dragonblood.pdf">
        <front>
          <title>Dragonblood: Analyzing the Dragonfly Handshake of WPA3 and
          EAP-pwd</title>

          <author>
            <organization>The Unicode Consortium</organization>
          </author>

          <date day="" month="" year="" />
        </front>
      </reference>

      <reference anchor="INS"
                 target="https://www.vodafone.com/about/vodafone-foundation/focus-areas/instant-schools">
        <front>
          <title>Vodafone Foundation Instant Schools for Sub-Saharan
          Africa</title>

          <author>
            <organization>The Unicode Consortium</organization>
          </author>

          <date day="" month="" year="" />
        </front>
      </reference>

      <!---->
    </references>
  </back>
</rfc>