Hi Guys, I have recently installed a 2008 R2 server with Sharepoint 2010 foundation and Windows 7 workstations (There are no other client OS'). I have configured split DNS on the 2008 server and it is configured to give itself as the first IP in DHCP and the ISP's DNS server as second. I have configured the sharepoint website to have an internal dns name of sharepoint.clientdomain.com (where clientdomain is the clients external domain name) and setup the split DNS to point this A record at the server, which works successfully. However, my client has noticed intermittent problems with the internal DNS when trying to connect to this DNS name, the workstation stops resolving the DNS name, the user loses connction to sharepoint and cannot ping the DNS name (it was possible to ping previously). I initially thought that the server DNS was the issue, but a restart of the DNS server and updating the server files did not resolve the issue, nor did an 'ipconfig /flushdns' on the workstation. I eventually restarted the 'DNS Client' service on the workstation and the problem was fixed, temporarily. The customer still complains of the issue and has resorted to using the IP of the server to access sharepoint, which they are not very happy about. Can anyone suggest what I can do to resolve this issue? The issue appears to be on the workstation. An example of the ipconfig is below: Windows IP Configuration Host Name . . . . . . . . . . . . : PC1 Primary Dns Suffix . . . . . . . : <domain>.local Node Type . . . . . . . . . . . . : Hybrid IP Routing Enabled. . . . . . . . : No WINS Proxy Enabled. . . . . . . . : No DNS Suffix Search List. . . . . . : <domain>.local Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : <domain>.local Description . . . . . . . . . . . : Broadcom NetXtreme Gigabit Ethernet Physical Address. . . . . . . . . : D4-85-64-AA-0E-3C DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes Link-local IPv6 Address . . . . . : fe80::e4bf:7b39:46b2:7ed5%12(Preferred) IPv4 Address. . . . . . . . . . . : 10.10.10.50(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Lease Obtained. . . . . . . . . . : Monday, 8 November 2010 3:41:27 PM Lease Expires . . . . . . . . . . : Tuesday, 23 November 2010 12:18:57 PM Default Gateway . . . . . . . . . : 10.10.10.1 DHCP Server . . . . . . . . . . . : 10.10.10.100 DHCPv6 IAID . . . . . . . . . . . : 265586020 DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-14-57-B7-33-D4-85-64-AA-0E-3C DNS Servers . . . . . . . . . . . : 10.10.10.100 203.0.178.191 NetBIOS over Tcpip. . . . . . . . : Enabled

I would not recommend that you use an internal DNS as primary and external as secondary. A client should be pointed to one or more DNS servers that host the same zones, otherwise, when the client communicates with the primary it will receive one response, and if it happens to communicate with secondary, the client will be unable to resolve any internal host names. All of your computers (including the DNS server) should point to one or more internal DNS servers. You can configure the DNS to perform forwarding to an external DNS server if you wish, otherwise, the DNS server by default will use its root hints to resolve external names. Visit: anITKB.com, an IT Knowledge Base.