Hello,
I have a new, small single-site DirectAccess 2-NIC Server 2016 VM serving a handful of Server 2016 and Windows 10 clients. The LAN is IPv4 only, and I'm using only IP-HTTPS for DA. All other IPv6 transition technologies are disabled on the clients via GPO. I also have the DA VM setup as an ISATAP router for manage-out with ISATAP limited by AD group and GPO to just the machines that need to manage-out and initiate RDP sessions to DA clients.
Here's where things get strange: Server 2016 DA clients register (and update) their IP-HTTPS IPv6 address in our internal AD DNS with no issue. Windows 10 DA clients do not. For the Win10 clients, manage-out (via RDP for example) works fine when using the IPv6 address instead of the host name. I have spent more hours than I care to admit with troubleshooting: going through countless Google searches, reading forum and blog posts, modifying AD, OU, and GPO settings, changing and uninstalling 3rd party AV products (that don't have a software firewall component), comparing DA troubleshooter logs, scouring event viewer entries, etc. At some point I realized all the Win10 clients are running the current 2004 build, so I decided to add a couple of laptops that are still running 1903. To my amazement, these clients registered IPv6 address, and I'm able to RDP by hostname from a manage-out machine. These Win10 clients are all in the same OU with the same AD group memberships.
Did something change in build 2004 that prevents the clients from registering their IPv6 address in DNS? The only differences I can find are in the event viewer system logs. The 2004 clients are littered with DNS Client Event warnings (IDs 8015 and 8018) stating that the system failed to register the A or AAAA resource records for the adapter name {long character sting here} on the DNS servers where the server IPs are the IPv4 IPs handed out by the IPv4 DHCP server of the network to which the machines are connected. I am not seeing any of these errors on the 1903 clients. I initially did not think much about this error because I'm also receiving the same error on the Server 2016 DA clients but of course those are able to register just fine internally, as noted above.
Has anyone else ran into this issue? Any ideas on how to fix it? Thanks.