Been having this issue for a while, but its becoming more frequent. We have two forests on our network. SiteA.local and SiteB.local. They are configured with a forest trust. Replication works fine. We have a problem in the individual forests. They both exhibit the same behavior. You can ping the NETBIOS name of any PC or server. You cannot ping the FQDN of anything unless you to an ipconfig /flushdns and /registerdns. This will work for a day, but then go right back to the same problem. This is on all servers and clients. Servers are all 2008 R2 Standard. Both Sites have primary and backup Active Directory Domains/DNS. That is, SRV1 is Primary Domain Controller/DNS and SRV2 is secondary Domain Controller and DNS. Clients are all Windows XP Professional or Windows 7 Professional. nslookup > SiteA.local Server: UnKnown Address: 10.8.208.10 Name: SiteA.local Addresses: 10.8.208.10 10.8.208.11 What further can I provide to help me solve this problem?

Can you give an ipconfig /all off of one of the clients? Your issue could be due to negative caching. If your client is using a DNS server that cannot resolve the record it will hold on to that "answer" even if the other DNS server can resolve. When you do a /flushdns it clears the cache.

FYI - This PC is static, but the DNS servers are the same on DHCP. Windows IP Configuration Host Name . . . . . . . . . . . . : Primary Dns Suffix . . . . . . . : SITEA.LOCAL Node Type . . . . . . . . . . . . : Hybrid IP Routing Enabled. . . . . . . . : No WINS Proxy Enabled. . . . . . . . : No DNS Suffix Search List. . . . . . : SITEA.LOCAL Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Intel(R) 82579LM Gigabit Network Connecti on Physical Address. . . . . . . . . : 00-22-4D-56-2C-9C DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes Link-local IPv6 Address . . . . . : fe80::d14d:b2a4:ca81:81b3%11(Preferred) IPv4 Address. . . . . . . . . . . : 10.8.208.99(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : 10.8.208.249 DHCPv6 IAID . . . . . . . . . . . : 234889805 DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-16-96-47-F4-00-22-4D-56-2C-9C DNS Servers . . . . . . . . . . . : 10.8.208.10 10.8.208.11 68.87.64.150 75.75.75.75 4.2.2.2 NetBIOS over Tcpip. . . . . . . . : Enabled

Any reason you have 3 other DNS servers listed aside from the 10.8.208.x servers? They all appear to be public - are your internal DNS servers configured for forwarding?

Any reason you have 3 other DNS servers listed aside from the 10.8.208.x servers? They all appear to be public - are your internal DNS servers configured for forwarding?

Hi rvdsabu4life, Thanks for posting here. I agree with Neil, clients should use only our internal DNS servers in his DNS server list and set forwarder on the DNS server it points in order to forward any domain it cant resolved to external public DNS server or the DNS server that hosts our trusted AD system. So could we first correct that on one of client with following what Neil suggested and see how is going . Using Query Forwarding http://technet.microsoft.com/en-us/library/cc816653(WS.10).aspx Meanwhile, please also try to test by disabling DNS cache on this client : How to Disable Client-Side DNS Caching in Windows http://support.microsoft.com/kb/245437 Thanks. Tiger LiTiger Li TechNet Community Support

Hi rvdsabu4life, Thanks for posting here. I agree with Neil, clients should use only our internal DNS servers in his DNS server list and set forwarder on the DNS server it points in order to forward any domain it cant resolved to external public DNS server or the DNS server that hosts our trusted AD system. So could we first correct that on one of client with following what Neil suggested and see how is going . Using Query Forwarding http://technet.microsoft.com/en-us/library/cc816653(WS.10).aspx Meanwhile, please also try to test by disabling DNS cache on this client : How to Disable Client-Side DNS Caching in Windows http://support.microsoft.com/kb/245437 Thanks. Tiger LiTiger Li TechNet Community Support

Hello, NEVER use external DNS servers on domain machines, so please remove ALL except the 10.x.x.x private ip range. That is your actual problem. After the change run ipconfig /flushdns and ipconfig /registernds and restart the netlogon service on DCs and reboot other domain machines. To have internet access for the domain computers configure the FORWARDERS on the DNS server properties in the DNS mangement console with the ISPs DNS server.Best regards Meinolf Weber MVP, MCP, MCTS Microsoft MVP - Directory Services My Blog: http://msmvps.com/blogs/mweber/ Disclaimer: This posting is provided AS IS with no warranties or guarantees and confers no rights.

This looks like it is going to work. I always used at least one internal and one external IP for DNS because thats how I was taught. Guess I was taught wrong :-X