Microsoft

Tech Tip: Share ODBC connections/Clean up DNS with scavenging

Windows 2000 Professional: Share ODBC connections

Windows 2000 supports Open Database Connectivity (ODBC), a standard mechanism developed by Microsoft to enable clients to access databases created by various database management systems without installing the DBMS on the client locally.

For example, you might create an ODBC connection on a server to enable access to a product database from the Web. The Web pages, hosted by IIS, include the calls necessary to access the ODBC connection and the underlying data.

Windows 2000 supports three kinds of ODBC data source names (DSNs): system, user, and file. Windows 2000 stores system and user DSNs in the registry. It stores file DSNs, however, as files with a .dsn file extension.

A common use for a file DSN is to provide a data connection for a local application, such as Excel or Access. The advantage of using a file DSN is that you can share it easily with users, either by placing it on a network share or by copying the DSN file to each user's computer.

To share file DSNs with users, use the Data Sources applet in the Administrative Tools applet of Control Panel to first create the DSN, and place the DSN in a location accessible to users. Users must add the DSN folder path to their respective application settings.

For example, if users are working in Excel, choose Data | Import External Data | New Database Query. In the Choose Data Source dialog box, click Options, enter the path to the shared DSN folder, and click OK to close both dialog boxes. The DSNs will then be available to other users within the application.

Windows 2000 Server: Clean up DNS with scavenging

Windows 2000's DNS service supports the scavenging feature, which helps you ensure that DNS records managed by the service are up to date. Scavenging is particularly important if you use Dynamic DNS to automatically register client host names when their IP addresses change, as is often the case when the clients receive address assignments through DHCP.

Over time, client host records in a zone can become stale, and scavenging removes these records. Removing the records improves DNS server and zone transfer performance, and it ensures that host records don't conflict with older records.

You can configure scavenging through a zone's properties. Open the DNS console, right-click the zone, and choose Properties. On the General tab, click Aging to open the Zone Aging/Scavenging Properties dialog box. Set the Refresh Interval and the No-refresh Interval using the drop-down lists, select the Scavenge Stale Resource Records check box, and click OK to close both dialog boxes.

You can also configure scavenging for zones globally, rather than for an individual zone, by editing the server's properties. In the DNS console, right-click the server, and choose Set Aging/Scavenging For All Zones. The resulting dialog box is the same as that for an individual zone.

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