{"id":10842,"date":"2010-09-08T07:09:00","date_gmt":"2010-09-08T07:09:00","guid":{"rendered":"https:\/\/aidanfinn.com\/?p=10842"},"modified":"2010-09-08T07:09:00","modified_gmt":"2010-09-08T07:09:00","slug":"windows-server-2008-r2-hyper-v-csv-and-ntlm","status":"publish","type":"post","link":"https:\/\/aidanfinn.com\/?p=10842","title":{"rendered":"Windows Server 2008 R2 Hyper-V CSV and NTLM"},"content":{"rendered":"<p>I went to my first IT conference in April 2004 \u2013 it was WinConnections in Vegas.&#160; It was there I heard people like Mark Minasi, Steve Riley, and Jeremy Moskowitz speaking for the first time.&#160; It was there that I started thinking beyond the off-the-shelf text book and training course.&#160; One of the things that came up was authentication security.&#160; Active Directory could use NTLM, NTLMv2, or Kerberos, with the latter being the most secure, and the former being not so good (I think they put it in stronger terms).<\/p>\n<p>The advice was to disable NTLM authentication across the network using GPO.&#160; I\u2019ve heard it dozens of times since.&#160; It seems to be accepted best practice.&#160; I\u2019ve seen it deployed countless times.<\/p>\n<p>We Hyper-V engineers\/administrators are going to have a problem with that.&#160; Cluster Shared Volume (CSV, the Windows Server 2008 R2 shared file system for clustered Hyper-V hosts) uses <a href=\"http:\/\/technet.microsoft.com\/en-us\/library\/ee830327(WS.10).aspx\" target=\"_blank\">NTLM authentication between the hosts<\/a>.&#160; Enabling a policy to disable NTLM will break CSV and cause the following alert:<\/p>\n<ul>\n<li><strong>ID: <\/strong>5121<\/li>\n<li><strong>Source: <\/strong>Microsoft-Windows-FailoverClustering<\/li>\n<li><strong>Version: <\/strong>6.1<\/li>\n<li><strong>Symbolic Name: <\/strong>DCM_VOLUME_NO_DIRECT_IO_DUE_TO_FAILURE<\/li>\n<li><strong>Message: <\/strong>Cluster Shared Volume &#8216;%1&#8217; (&#8216;%2&#8217;) is no longer directly accessible from this cluster node<\/li>\n<\/ul>\n<p>This is another situation where security auditors will try to enforce policy that will break things for us (the other is antivirus on the host).&#160; You will need an exception to this policy for all clustered Hyper-V computer objects.&#160; You can do this by using a security group to filter the offending policy in question.&#160; That will require a single GPO to apply this one setting.&#160; Alternatively you can create and link another GPO that applies just to the clustered hosts.&#160; This GPO will enable NTLM.<\/p>\n<div style=\"padding-bottom: 0px; margin: 0px; padding-left: 0px; padding-right: 0px; display: inline; float: none; padding-top: 0px\" id=\"scid:0767317B-992E-4b12-91E0-4F059A8CECA8:a41a2c28-cf44-4ffb-9657-24d15b0dd477\" class=\"wlWriterEditableSmartContent\">Technorati Tags: <a href=\"http:\/\/technorati.com\/tags\/Virtualisation\" rel=\"tag\">Virtualisation<\/a>,<a href=\"http:\/\/technorati.com\/tags\/Failover+Clustering\" rel=\"tag\">Failover Clustering<\/a>,<a href=\"http:\/\/technorati.com\/tags\/Hyper-V\" rel=\"tag\">Hyper-V<\/a>,<a href=\"http:\/\/technorati.com\/tags\/Windows+Server+2008+R2\" rel=\"tag\">Windows Server 2008 R2<\/a><\/div>\n","protected":false},"excerpt":{"rendered":"<p>I went to my first IT conference in April 2004 \u2013 it was WinConnections in Vegas.&#160; It was there I heard people like Mark Minasi, Steve Riley, and Jeremy Moskowitz speaking for the first time.&#160; It was there that I started thinking beyond the off-the-shelf text book and training course.&#160; One of the things that &hellip; <a href=\"https:\/\/aidanfinn.com\/?p=10842\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;Windows Server 2008 R2 Hyper-V CSV and NTLM&#8221;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_uf_show_specific_survey":0,"_uf_disable_surveys":false,"footnotes":""},"categories":[20],"tags":[63,181,195,117],"class_list":["post-10842","post","type-post","status-publish","format-standard","hentry","category-hyper-v","tag-failover-clustering","tag-hyper-v","tag-virtualisation","tag-windows-server-2008-r2"],"aioseo_notices":[],"jetpack_featured_media_url":"","amp_enabled":true,"_links":{"self":[{"href":"https:\/\/aidanfinn.com\/index.php?rest_route=\/wp\/v2\/posts\/10842","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/aidanfinn.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/aidanfinn.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/aidanfinn.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/aidanfinn.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=10842"}],"version-history":[{"count":0,"href":"https:\/\/aidanfinn.com\/index.php?rest_route=\/wp\/v2\/posts\/10842\/revisions"}],"wp:attachment":[{"href":"https:\/\/aidanfinn.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=10842"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/aidanfinn.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=10842"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/aidanfinn.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=10842"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}