Hello,

recently we started having problems on our TMG server. After looking a bit into it I've found out that somehow DNS stops responding for TMG and only restores after TMG server reboot.

This happens few times in a week on various hours, but mostly at night.

When problem occurs if I try to use nslookup on TMG server, this is what I see:

C:\Users\Administrator>nslookup
Default Server:  UnKnown
Address:  10.1.1.7

IP address is correct, but the hostname for some reason is UnKnown. I've read that this can be caused incorrect reverse DNS configuration, but this is not the case as after server restart it works fine and it worked without problems at all until recently. Also DNS responds fine on our other computers, so this must be issue on TMG server.

I can ping DNS hostname and IP, I can also telnet to 53 port of DN server successfully from TMG server.

our adapter configuration looks like this:

Windows IP Configuration

   Host Name . . . . . . . . . . . . : tmg
   Primary Dns Suffix  . . . . . . . : domain.com
   Node Type . . . . . . . . . . . . : Hybrid
   IP Routing Enabled. . . . . . . . : Yes
   WINS Proxy Enabled. . . . . . . . : No
   DNS Suffix Search List. . . . . . : domain.com

PPP adapter RAS (Dial In) Interface:

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : RAS (Dial In) Interface
   Physical Address. . . . . . . . . :
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   IPv4 Address. . . . . . . . . . . : 10.33.0.1(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.255
   Default Gateway . . . . . . . . . :
   NetBIOS over Tcpip. . . . . . . . : Enabled

Ethernet adapter LAN:

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Intel(R) PRO/1000 MT Network Connection #
2
   Physical Address. . . . . . . . . : xx-xx-xx-xx-xx-xx
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   IPv4 Address. . . . . . . . . . . : 10.1.1.253(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.254.0
   Default Gateway . . . . . . . . . :
   DNS Servers . . . . . . . . . . . : 10.1.1.7
                                       10.1.1.1
   NetBIOS over Tcpip. . . . . . . . : Enabled

Ethernet adapter Inet:

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Intel(R) PRO/1000 MT Network Connection
   Physical Address. . . . . . . . . : yy-yy-yy-yy-yy-yy
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   IPv4 Address. . . . . . . . . . . : xxx.xxx.xx.xx(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.240
   IPv4 Address. . . . . . . . . . . : xxx.xxx.xx.xx(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.240
   IPv4 Address. . . . . . . . . . . : xxx.xxx.xx.xx(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.240
   IPv4 Address. . . . . . . . . . . : xxx.xxx.xx.xx(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.240
   IPv4 Address. . . . . . . . . . . : xxx.xxx.xx.xx(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.240
   IPv4 Address. . . . . . . . . . . : xxx.xxx.xx.xx(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.240
   IPv4 Address. . . . . . . . . . . : xxx.xxx.xx.xx(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.240
   Default Gateway . . . . . . . . . : xxx.xxx.xx.xx
   NetBIOS over Tcpip. . . . . . . . : Enabled

C:\Users\Administrator>

Hi,

Thank you for the post.

Please run TMG BPA on the server to check if there is any configuration error.

Regards,

Hello,

I have run TMG BPA, but did not see any errors I could relate to our problem. Ended up reinstalling TMG on fresh server and restoring rules there. Will post back if problem reoccurs.

Hello, after reinstalling everything was fine until a week ago the problem reappeared.

Have no idea what is causing this.