Configuring DNS for the Internal Network

When using the default configuration tools for setting up the server and workstations in an SBS environment, the network configuration should be set correctly for each computer to allow proper internal and external name resolution. Sometimes, however, knowing what should happen is not sufficient. Knowing what actually happens and comparing that to what should happen can shed light on problems you may encounter.

Standard DNS Server Configuration

The network portion of the Connect to the Internet Wizard, also known as the CEICW (Configure Email and Internet Connection Wizard) configures the network settings for both the internal and external network interfaces. As it relates to DNS, the NIC setup is straightforwardboth interfaces reference the internal NIC's IP address as the DNS server. The following output of an ipconfig /all command in a command prompt shows a proper network configuration for a two-network card configuration after the CEICW has been run:

[View full width]
C:\Documents and Settings\Administrator>ipconfig /all Windows IP Configuration    Host Name . . . . . . . . . . . . : sbs    Primary Dns Suffix  . . . . . . . : SmallBizCo.local    Node Type . . . . . . . . . . . . : Unknown    IP Routing Enabled. . . . . . . . : Yes    WINS Proxy Enabled. . . . . . . . : Yes    DNS Suffix Search List. . . . . . : SmallBizCo.local Ethernet adapter Server Local Area Connection:    Connection-specific DNS Suffix  . :    Description . . . . . . . . . . . : 3Com 3C920 Integrated Fast Ethernet Controller  (3C905C-TX Compatible)    Physical Address. . . . . . . . . : 00-08-74-40-5B-61    DHCP Enabled. . . . . . . . . . . : No    IP Address. . . . . . . . . . . . : 192.168.16.2    Subnet Mask . . . . . . . . . . . : 255.255.255.0    Default Gateway . . . . . . . . . :    DNS Servers . . . . . . . . . . . : 192.168.16.2    Primary WINS Server . . . . . . . : 192.168.16.2 Ethernet adapter Network Connection:    Connection-specific DNS Suffix  . :    Description . . . . . . . . . . . : Realtek RTL8029(AS) PCI Ethernet Adapter    Physical Address. . . . . . . . . : 00-C0-F0-2B-7D-F9    DHCP Enabled. . . . . . . . . . . : No    IP Address. . . . . . . . . . . . : 10.10.1.9    Subnet Mask . . . . . . . . . . . : 255.255.255.0    Default Gateway . . . . . . . . . : 10.10.1.1    DNS Servers . . . . . . . . . . . : 192.168.16.2    Primary WINS Server . . . . . . . : 192.168.16.2    NetBIOS over Tcpip. . . . . . . . : Disabled C:\Documents and Settings\Administrator> 

As you can see from the output, both the external and internal NICs point to the internal NIC for DNS. This forces all DNS lookups on the server to use the DNS Server service on the server to provide all name resolution.

Standard DNS Workstation Configuration

In general, workstations in an SBS environment should be configured to use DHCP to get their network configuration. In some cases, however, some workstations may be required to have a static IP configuration. The following listing shows the output from an ipconfig /all command for a standard workstation configuration:

[View full width]
C:\Documents and Settings\Administrator>ipconfig /all Windows IP Configuration         Host Name . . . . . . . . . . . . : JONDOUGH01         Primary Dns Suffix  . . . . . . . : SmallBizCo.local         Node Type . . . . . . . . . . . . : Hybrid         IP Routing Enabled. . . . . . . . : No         WINS Proxy Enabled. . . . . . . . : No         DNS Suffix Search List. . . . . . : SmallBizCo.local                                             SmallBizCo.local Ethernet adapter Server Area Connection:         Connection-specific DNS Suffix  . : SmallBizCo.local         Description . . . . . . . . . . . : Intel 21140-Based PCI Fast Ethernet Adapter  (Generic)         Physical Address. . . . . . . . . : 00-03-FF-81-79-85         Dhcp Enabled. . . . . . . . . . . : Yes         Autoconfiguration Enabled . . . . : Yes         IP Address. . . . . . . . . . . . : 192.168.16.16         Subnet Mask . . . . . . . . . . . : 255.255.255.0         Default Gateway . . . . . . . . . : 192.168.16.2         DHCP Server . . . . . . . . . . . : 192.168.16.2         DNS Servers . . . . . . . . . . . : 192.168.16.2         Primary WINS Server . . . . . . . : 192.168.16.2         Lease Obtained. . . . . . . . . . :         Lease Expires . . . . . . . . . . : C:\Documents and Settings\Administrator> 

When setting the network configuration manually for a workstation, a few items must be configured correctly for the workstation to communicate correctly with the SBS network. First, the IP address and subnet mask must match the IP address range used for the internal network. Second, the default gateway must point to the SBS server's internal NIC (for a dual-NIC SBS configuration) or to the router/firewall (for a single-NIC SBS configuration). Third, the DNS server must be set to the SBS server's internal NIC. The ipconfig /all output from a workstation with a correctly configured network configuration looks like the following listing:

[View full width]
C:\Documents and Settings\Administrator>ipconfig /all Windows IP Configuration         Host Name . . . . . . . . . . . . : JONDOUGH01         Primary Dns Suffix  . . . . . . . : SmallBizCo.local         Node Type . . . . . . . . . . . . : Broadcast         IP Routing Enabled. . . . . . . . : No         WINS Proxy Enabled. . . . . . . . : No         DNS Suffix Search List. . . . . . : SmallBizCo.local Ethernet adapter Network Connection:         Connection-specific DNS Suffix  . :         Description . . . . . . . . . . . : Intel 21140-Based PCI Fast Ethernet Adapter  (Generic)         Physical Address. . . . . . . . . : 00-03-FF-81-79-85         Dhcp Enabled. . . . . . . . . . . : No         IP Address. . . . . . . . . . . . : 192.168.16.201         Subnet Mask . . . . . . . . . . . : 255.255.255.0         Default Gateway . . . . . . . . . : 192.168.16.2         DNS Servers . . . . . . . . . . . : 192.168.16.2 C:\Documents and Settings\Administrator> 

The workstation should not be configured to look to any other DNS servers besides the SBS server. If a secondary DNS server must be configured for a workstation, the SBS server's IP address must be listed first.

Best Practice: ipconfig /all

Anytime the server or workstation experiences communication difficulties, checking the network configuration of both with the ipconfig /all command is the first step to identifying where the problem lies. If you post in the SBS newsgroups or call Microsoft PSS for assistance, one of the first questions you are likely to be asked is to provide the output from this command for both the server and a workstation on the network.

To prepare the output from ipconfig /all for posting in a newsgroup or sending to a support professional in email, you'll need to save the output from the command to a file. The easiest way to do this is to enter the following command from a command prompt:

ipconfig /all > ipconfig.txt 

This creates a text file named ipconfig.txt in the current working directory. The file can be opened in Notepad for review. One other quick way to create the file and review it immediately is to use the following command in the command window:

ipconfig /all > ipconfig.txt && ipconfig.txt 

This command creates the ipconfig.txt file in the current working directory and immediately opens the file with Notepad.