Managing IP Addresses

Applies To: Windows SBS 2008

Using a static Internet IP addresses

The Internet IP address is set on the external network port on your router. If you need to set or change a static Internet IP address on your router, you must change it in the router management console. For information about how to access the router management console from the Windows SBS Console, see Configure your router, later in this document. For information about how to configure your router, see the documentation for your router manufacturer.

Changing the local IP address on the server

During installation Windows SBS 2008 searches for a router. If it finds a router that has a valid IP address, Setup configures the local network adapter on the server with a static IP address in the same range as the router. For example, if the router’s internal network port IP address is, then the server’s IP address is All network-related services are set up to use IP addresses in the same range.

If you must change the static IP address on the server to a new subnet for any reason, you must also change the static IP address on the internal network port on the router, and then run the Fix My Network Wizard to ensure that all network services use the new IP address range. For information about running the wizard, see Run the Fix My Network Wizard, later in this document.

Using IPv6

During Windows SBS 2008 installation, a static Internet Protocol version 6 (IPv6) address is automatically configured on the server. Because many applications are programmed to use IPv4, Windows SBS 2008 runs IPv4 and IPv6 on the same network, either wired or wireless. Windows SBS 2008 also configures DHCP and DNS for IPv6. For the server to use IPv6 to reach the Internet, you must have a stateless, autoconfigured IPv6 router connecting your local network to the Internet.

Exchange Server and e-mail services require that you continue to run IPv4 on your local network.

Using reverse DNS

DNS resolves a known domain name or host name to an IP address. Reverse DNS resolves a known IP address to a domain name or a host name. For example, if you want to know the host name for the IP address, you use reverse DNS, which can resolve the address to

One of the applications of reverse DNS on the Internet is to act as a spam filter. For example, reverse DNS would recognize if a malicious user is using an IP address that is not valid and does not resolve to a domain name. A reverse DNS lookup program checks the IP addresses of incoming messages against a DNS database. If no valid name matches the IP address, the server blocks that message.

Most Internet service providers (ISPs) support reverse DNS when you purchase a static IP address from them. To help your e-mail messages get through spam filters, contact your ISP to set up reverse DNS for your domain name.

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