Understanding DNS Caching

Proxy Server supports DNS caching to reduce the number of DNS lookups performed by the proxy while it resolves DNS host names into IP addresses.

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.

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 DNS caching.

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

   The default size is 1024.

5. Set the DNS cache expiration time.

   The Proxy Server purges DNS cache entries from the cache when it reaches a pre-set expiration time. The default DNS expiration time 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.