"DNS suffixes" are used for resolving unqualified domain names (names with no dots).
In the Windows Control Panel, double-click the "Network and Dial-up Connections" (or "Network Connections" on Windows XP / 2003) icon:
Right-click a network connection icon and select "Properties" from the pop-up menu:
In the network connection Properties dialgo, select "Internet Protocol (TCP/IP)" and click the "Properties" button:
In the "Internet Protocol (TCP/IP) Properties" dialog, click the "Advanced..." button:
In the "Advanced TCP/IP Settings" dialog, select the "DNS" tab, and specify which DNS suffixes to use for resolving unqualified domain names:
If you choose the first (and default) option to append primary and connection specific DNS suffixes, then you will also need to configure the primary DNS suffix. See reference articles below.
For more information, please see the following knowledge base articles: