ISATAP

<h2 id="criticisms-of-isatap">Criticisms of ISATAP</h2>
<p>ISATAP typically builds its Potential Router List (PRL) by consulting the DNS; hence, in the <a href="/facts/OSI_model/oxN9Xhjz">OSI model</a> it is a lower-layer protocol that relies on a higher layer.  A circularity is avoided by relying on an IPv4 DNS server, which does not rely on IPv6 routing being established; however, some network specialists claim that these violations lead to insufficient protocol robustness.<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a>[<i>better source needed</i>]
</p><p>ISATAP carries the same security risks as 6over4: the IPv4 virtual link must be delimited carefully at the network edge, so that external IPv4 hosts cannot pretend to be part of the ISATAP link. That is normally done by ensuring that <i>proto-41</i> (<a href="/facts/6in4/yzjhTMwq">6in4</a>) cannot pass through the <a href="/facts/Firewall_(computing)/Et2RkJaU">firewall</a>.
</p>
<h2 id="implementations-of-isatap">Implementations of ISATAP</h2>
<p>ISATAP is implemented in Microsoft <a href="/facts/Windows_XP/IozrkAYS">Windows XP</a>, <a href="/facts/Windows_Vista/IASEUCTB">Windows Vista</a>, <a href="/facts/Windows_7/tldLdbnX">Windows 7</a>, <a href="/facts/Windows_8/eRtw96T3">Windows 8</a>, <a href="/facts/Windows_10/be9IHehJ">Windows 10</a>, <a href="/facts/Windows_Server_2008/hrcPjTCH">Windows Server 2008</a>, <a href="/facts/Windows_Server_2012/W1vuUlSB">Windows Server 2012</a>, <a href="/facts/Windows_Server_2016/LBMMCjYC">Windows Server 2016</a>, <a href="/facts/Windows_Server_2019/pYAj0Xv4">Windows Server 2019</a>, <a href="/facts/Windows_Mobile/YfskR7FS">Windows Mobile</a>, <a href="/facts/Linux/9FvCKSTq">Linux</a>, and in <a href="/facts/Cisco_IOS/jwcRuzX8">Cisco IOS</a> (since IOS 12.2(14)S and IOS XE Release 2.1).<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a>
</p><p>Due to a <a href="/facts/Patent_infringement/7vH9JvMF">patent claim</a>, early in-<a href="/facts/Kernel_(operating_system)/uEj4U3Rz">kernel</a> implementations were withdrawn from both <a href="/facts/KAME_project/Bsbto2fH">KAME</a> (*<a href="/facts/Berkeley_Software_Distribution/XQKcURrh">BSD</a>) and USAGI (Linux). However, the <a href="/facts/Internet_Engineering_Task_Force/tIcCsFhX">IETF</a> IPR disclosure search engine reports that the would-be infringing patent's holder requires no license from implementers.<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a>  ISATAP support has been supported in Linux since kernel version 2.6.25,<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a> the tool isatapd <a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a> provides a userspace helper.  For prior kernels, the open source project <a href="/facts/Miredo/2sc0SEws">Miredo</a> provided an incomplete userland ISATAP implementation, which was removed in version 1.1.6.
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<h2 id="external-links">External links</h2>
<ul><li><a href="https://web.archive.org/web/20200730191027/http://www.isatap.org/">isatap.org Archive</a> at the <a href="/facts/Wayback_Machine/nmQ3a6JC">Wayback Machine</a> (archived 2020-07-30)</li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>Templin, Fred L.; Gleeson, Tim; Thaler, Dave (March 2008). "Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) RFC 5214". tools.ietf.org. IETF Network Working Group. doi:10.17487/RFC5214. Retrieved 25 November 2020. Category: Informational <a href="https://tools.ietf.org/html/rfc5214" target="_blank">https://tools.ietf.org/html/rfc5214</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>itojun (2002-12-25). "Request to publish ISATAP". v6ops Mailing List. Retrieved 2015-02-09. <a href="http://www.psg.com/lists/v6ops/v6ops.2002/msg01045.html" target="_blank">http://www.psg.com/lists/v6ops/v6ops.2002/msg01045.html</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>"Cisco IOS IPv6 Command Reference". Retrieved 2015-05-06. <a href="http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipv6/command/ipv6-cr-book/ipv6-s6.html#wp2787421125" target="_blank">http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipv6/command/ipv6-cr-book/ipv6-s6.html#wp2787421125</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>Peter Marcotullio (2005-03-15). "SRI International's statement about IPR claimed in draft-ietf-ngtrans-isatap-24.txt". Retrieved 2015-02-09. <a href="https://datatracker.ietf.org/ipr/550/" target="_blank">https://datatracker.ietf.org/ipr/550/</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
<li id="fn:5"><p>Fred L. Templin (2007-11-29). "IPV6: Add RFC4214 support". Retrieved 2015-02-09. <a href="https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=c7dc89c0ac8e7c3796bff91becf58ccdbcaf9f18" target="_blank">https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=c7dc89c0ac8e7c3796bff91becf58ccdbcaf9f18</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li>
<li id="fn:6"><p>Sascha Hlusiak (2010). "ISATAP client for Linux". Retrieved 2015-02-09. <a href="http://www.saschahlusiak.de/linux/isatap.htm" target="_blank">http://www.saschahlusiak.de/linux/isatap.htm</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li>
</ol>

ISATAP open-in-new

ISATAP