Server Management and Maintenance: how to clear DNS Cache correctly

Windows 2000 automatically starts the DNS Client Service, which provides the Client name resolution and cache service. Your DNS query results are cached locally. When configuring a DNS server, if you do not have a good grasp of this principle, some incorrect operations will often occur.

You can use the command at the command prompt to clear the information in the DNS client cache. Run the "Ipconfig/flushdns" command on the client. If the drive letter is prompted, run the "ping" command to solve the problem.

It is worth noting that, open the "service" tool in "Administrative Tools" and find the "DNS Client" item. After the service is stopped, the DNS query information will not be cached on the Client, in this way, the modifications made on the DNS server can be immediately reflected when the client re-queries.

When there is a problem with domain name resolution, it may be that the DNS server updates the IP address of this domain name, but it does not correspond to the information stored in the local DNS cache, resulting in domain name resolution problems, in this case, you need to update the local DNS local cache and simply clear the local DNS local cache.

1. Enter cmd in the running process, and then enter ipconfig/flushdns.

2. Stop the dns client Service in the system service. You can not store the DNS query information locally.

3. Disable IE, and then clear the history or restart machine.

Domain names can be correctly resolved immediately in any of the three methods. Allows users to share ODBC connections to Windows 2000 and supports open database connections to ODBC), a standard mechanism developed by Microsoft, it allows customers to access databases created by various database management systems without having to install DBMS locally.

For example, you can create an ODBC connection on a server to access a product database from the Web. Web pages that use IIS as the host system can contain necessary calls to access ODBC connections and underlying data.

Windows 2000 supports three ODBC Data Source names: system, user, and file. Windows 2000 systems and user DSN are stored in the registry. The file DSN is a file suffixed with. dsn.

File DSN is generally used to provide database connection for local applications, such as Excel or Access. The advantage of using the folder DSN is that you can easily share it among users, and you can share or copy the DSN File to each user's computer through the network.

To share a file DSN between users, use the data source applet under the management tool Applet in the control panel to first create a DSN, and then place the DSN in a place that users can access. You must add the DSN folder path to their corresponding application settings.

For example, if you use Excel, select import data to external data to create a database query. In the Select data source dialog box, click Options, enter the path of the shared DSN folder, and click Close. Then other users can use DSN in the application.

Use scavenging to clear DNS

Windows 2000 DNS supports scavenging, which helps you ensure that DNS records managed by the service are updated. If you use dynamic DNS to automatically register their host names after the customer's IP address is changed, scavenging is very important. This happens as much as the customer automatically obtains the IP address through DHCP.

Over time, client host records in a region may become obsolete, and scavenging deletes these records. Deleting records can improve the DNS server and regional transmission performance, and ensure that host records are not old record conflicts.

You can configure scavenging through the attribute of a region. Open the DNS console, right-click the Zone, and select Properties. On the General tab, click Aging to open the Zone Aging/Scavenging Properties dialog box. Use the drop-down list box to set Refresh Interval and Non-refresh Interval, select the Scavenge Stale Resource Records check box, and click OK to close these two dialog boxes. You can also configure scavenging for the overall region by editing the server attributes, rather than configuring a single region. On the DNS console, right-click the server and choose Set Aging/Scavenging For All Zones. The pop-up dialog box is the same as the dialog box for configuring a single region.

Delegate A Policy Group Object

Use Ipconfig to observe and manage DNS resolution caches

DNS customers on Windows Professional platform resolve their host names to IP addresses, which is the same as those on other Windows operating platforms. DNS resolution requires support for Web browsers, as well as support for mail services and other applications that depend on host names rather than IP addresses.

Windows DNS resolution stores the DNS query results, including affirmative queries, and of course queries that do not query resolution failures ).

Each DNS record has a TTL value. This value determines when the record is refreshed and is replaced by other queries. Before TTL is reached, Windows DNS returns the cached query results without starting a new query.

When you want to solve the connection and DNS problems, it is necessary to clear the DNS Cache and force Windows to perform a new resolution on a host name. You can use the IPConfig console command to observe the cache capacity and clear the cache.

You can run the following command to display the cache capacity and send the result to the More command to display the result on one page at a time: ipconfig/displaydns more

Run this command to clear the cache: ipconfig/flushdns

Delegate A Policy Group Object

As the network expands, especially when you need to manage policy groups across different departments or regions, you will find it increasingly difficult to manage servers and networks. Policy Group Control Object GPOs) delegated control can help simplify your management. The delegated administrator can manage policy groups for organizations with special organizational units (Ous) or domains as needed.

Authorize the GPO management to set the GPO access control table to control the user's read/write access. The specific settings are as follows:

1. Open the Active Directory user and computer console

2. Right-click the OU connected to GPO, expand the domain, and select Properties;

3. Click the rule group label, select GPO, and click Properties;

4. Click the security label to add the group or user entrusted with GPO, and select allow read and write operations;

5. Click OK to close the GPO attribute bar, and then press OK to close the OU attribute bar;