I am having a very difficult problem with a newer Windows Server 2008 R2 and TMG 2010 installation.
I am losing connectivity with my internal DNS servers for up to minutes at a time. I think it may be happening to Windows 7 clients as well but it is very irregular and it is not happening to my work station so it is difficult to catch. The big problem with the TMG server is that when communication with the DNS server is cut off the proxy server will either take a very long time to respond to time out completely.
I have checked the logs of all of the servers involved and I do not have any error messages: 1 TMG server, 2 DNS servers (both AD controllers), 1 Hyper V server hosting 1 DNS server.
The only change I made to the environment at the time this started to happen was to install WSUS on the DNS server running on HyperV. I had a problem with it downloading all of the updates during business hours and uninstalled it a few hours later.
I do not see anything in the Event logs related to network or the DNS server.
I have tried a netmon capture on the TMG server and while I am not an expert on reading the traces I could not see anything obvious.
And just starting today I am starting to loose connection to the RDC on the TMG server for a couple of minutes at a time. But while I am not able to connect to the server I am able ping it.
All network drivers on the DNS Server and the TMG server are up to date.
I created an alert on the TMG server to alert me when connectifity is lost to the two DNS servers. During the day I get a many errors going to DNS server 1 (prefered) and maybe a couple errors going to server 2 (alternate).
The only DNS errors I can find through diagnostics are if I run dcdiag /test:dns which give me the following:
DNS server: 2001:500:1::803f:235 (h.root-servers.net.)
1 test failure on this DNS server
PTR record query for the 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa failed on the DNS server 2001:500:1::803f:235
DNS server: 2001:500:2f::f (f.root-servers.net.)
1 test failure on this DNS server
PTR record query for the 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa failed on the DNS server 2001:500:2f::f
DNS server: 2001:500:3::42 (l.root-servers.net.)
1 test failure on this DNS server
PTR record query for the 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa failed on the DNS server 2001:500:3::42
DNS server: 2001:503:ba3e::2:30 (a.root-servers.net.)
1 test failure on this DNS server
PTR record query for the 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa failed on the DNS server 2001:503:ba3e::2:30
DNS server: 2001:503:c27::2:30 (j.root-servers.net.)
1 test failure on this DNS server
PTR record query for the 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa failed on the DNS server 2001:503:c27::2:30
DNS server: 2001:7fd::1 (k.root-servers.net.)
1 test failure on this DNS server
PTR record query for the 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa failed on the DNS server 2001:7fd::1
DNS server: 2001:7fe::53 (i.root-servers.net.)
1 test failure on this DNS server
PTR record query for the 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa failed on the DNS server 2001:7fe::53
DNS server: 2001:dc3::35 (m.root-servers.net.)
1 test failure on this DNS server
PTR record query for the 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa failed on the DNS server 2001:dc3::35
......................... franksville.quickcable.com passed test DNS
I have never done anything with IPv6 on any of the machines prior to this problem.
I have tried disabling the IPv6 protocol on all of the servers involved but this did not change a thing.