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Display and view a client resolver cache using the ipconfig command

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Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

To display and view a client resolver cache using the ipconfig command

  1. Open Command Prompt.

  2. Type:

    ipconfig /displaydns

Value Description

ipconfig

The name of the command-line program.

/displaydns

The command to display a client resolver cache.

Notes

  • Performing this task does not require you to have administrative credentials. Therefore, as a security best practice, consider performing this task as a user without administrative credentials.

  • To open a command prompt, click Start, point to All programs, point to Accessories, and then click Command prompt.

  • To view the complete syntax for this command, at a command prompt, type:

    ipconfig /help

  • To pause the display of the command output to one screen at time, type ipconfig /displaydns|more.

  • The ipconfig /displaydns command provides you with a means to view the contents of the DNS client resolver cache, which includes entries preloaded from the local Hosts file, as well as any recently obtained resource records for name queries resolved by the system. This information is used by the DNS Client service to quickly resolve frequently queried names before it queries its configured DNS servers.

  • When the ipconfig /displaydns command is used to display current resolver cache contents, the resultant output generally includes the local host and loopback IP address (127.0.0.1) mappings. This is because these mappings typically exist in the default (unmodified) contents of the local Hosts file.

  • After you can add host mapping entries to the local Hosts file and save the file, these entries are added to the displayed output of this command. For more information, see Related Topics.

  • The resolver cache can also support negative caching of unresolved or non-valid DNS names. These entries are added by the DNS Client service when it receives a negative answer from a DNS server for a queried name. The negative result is cached for a short period of time so that it is not again queried, which could cause query performance problems.

    During DNS troubleshooting, you can flush and reset the cache to discard negative entries from the cache and any other dynamically added entries that were not preloaded. For more information, see Related Topics.

  • Although the ipconfig command is provided for earlier versions of Windows, the /displaydns option is only available for use on computers running Windows 2000, Windows XP, or Windows Server 2003 operating systems.

Information about functional differences

  • Your server might function differently based on the version and edition of the operating system that is installed, your account permissions, and your menu settings. For more information, see Viewing Help on the Web.

See Also

Concepts

Preload the client resolver cache
Flush and reset a client resolver cache using the ipconfig command
Client features
DNS tools
Ipconfig