Configuring the DNS Cache

The Configure DNS Cache page is used to enable or disable DNS caching, set the size of the DNS cache, set the expiration of DNS cache entries, and enable or disable negative DNS caching.

The proxy server optionally maintains a "Client DNS cache" and a "Host DNS cache" to store the results of ipaddress to hostname lookups done on clients and hostname to ipaddress lookups done on remote hosts, respectively. The "Configure DNS Cache" page is used to configure both types of caches.

To Configure the DNS Cache

1. Access the Server Manager and click the Preferences tab.

2. Click the Configure DNS Cache link.

   The Configure DNS Cache page is displayed.

3. Enable or disable Host/Client DNS caching.

4. Select the number of entries from the Host/Client DNS Cache Size drop-down list that can be stored in the Host/Client DNS cache.

   The default size is 1024.

5. Set the Host/Client DNS cache expiration time.

   The Proxy Server purges Host/Client DNS cache entries from the cache when it reaches a pre-set expiration time. The default DNS expiration time for both Host and Client DNS caches is 20 minutes.

6. Enable or disable caching of errors when the host name is not found.

7. Click OK.

8. Click Restart Required.

   The Apply Changes page is displayed.

9. Click the Restart Proxy Server button to apply the changes.