Skip to main content

Does IPCONFIG /FLUSHDNS do anything other than clear the cache?

According to Microsoft Documentation, no it does not.  Below is a list of the functions of IPCONFIG.  Noticed that FlushDNS only clears the cache.

/all : Displays the full TCP/IP configuration for all adapters. Without this parameter, ipconfig displays only the IP address, subnet mask, and default gateway values for each adapter. Adapters can represent physical interfaces, such as installed network adapters, or logical interfaces, such as dial-up connections.

/renew [Adapter] : Renews DHCP configuration for all adapters (if an adapter is not specified) or for a specific adapter if the Adapter parameter is included. This parameter is available only on computers with adapters that are configured to obtain an IP address automatically. To specify an adapter name, type the adapter name that appears when you use ipconfig without parameters.

/release [Adapter] : Sends a DHCPRELEASE message to the DHCP server to release the current DHCP configuration and discard the IP address configuration for either all adapters (if an adapter is not specified) or for a specific adapter if the Adapter parameter is included. This parameter disables TCP/IP for adapters configured to obtain an IP address automatically. To specify an adapter name, type the adapter name that appears when you use ipconfig without parameters.

/flushdns : Flushes and resets the contents of the DNS client resolver cache. During DNS troubleshooting, you can use this procedure to discard negative cache entries from the cache, as well as any other entries that have been added dynamically.

/displaydns : Displays the contents of the DNS client resolver cache, which includes both entries preloaded from the local Hosts file and any recently obtained resource records for name queries resolved by the computer. The DNS Client service uses this information to resolve frequently queried names quickly, before querying its configured DNS servers.

/registerdns : Initiates manual dynamic registration for the DNS names and IP addresses that are configured at a computer. You can use this parameter to troubleshoot a failed DNS name registration or resolve a dynamic update problem between a client and the DNS server without rebooting the client computer. The DNS settings in the advanced properties of the TCP/IP protocol determine which names are registered in DNS.

/showclassid Adapter : Displays the DHCP class ID for a specified adapter. To see the DHCP class ID for all adapters, use the asterisk (*) wildcard character in place of Adapter. This parameter is available only on computers with adapters that are configured to obtain an IP address automatically.

/setclassid Adapter [ClassID] : Configures the DHCP class ID for a specified adapter. To set the DHCP class ID for all adapters, use the asterisk (*) wildcard character in place ofAdapter. This parameter is available only on computers with adapters that are configured to obtain an IP address automatically. If a DHCP class ID is not specified, the current class ID is removed.

/?: Displays help at the command prompt.

Comments

Popular posts from this blog

How to list all the AD LDS instances on a server

AD LDS allows you to provide directory services to applications that are free of the confines of Active Directory.  To list all the AD LDS instances on a server, follow this procedure: Log into the server in question Open a command prompt. Type dsdbutil and press Enter Type List Instances and press Enter . You will receive a list of the instance name, both the LDAP and SSL port numbers, the location of the database, and its status.

How to run GPResult on a remote client with PowerShell

In the past, to run the GPResult command, you would need to either physically visit this client, have the user do it, or use and RDP connection.  In all cases, this will disrupt the user.  First, you need PowerShell remoting enabled on the target machine.  You can do this via Group Policy . Open PowerShell and type this command. Invoke-Command –ScriptBlock {GPResult /r} –ComputerName <ComputerName> Replace <ComputerName> with the name of the target.  Remember, the target needs to be online and accessible to you.

Error icon when creating a GPO Preference drive map

You may not have an error at all.  Take a look at the drive mapping below. The red triangle is what threw us off.  It is not an error.  It is simply a color representation of the Replace option of the Action field in the properties of the drive mappings. Create action This give you a green triangle. The Create action creates a new mapped drive for users. Replace Action The Replace action gives you a red triangle.  This action will delete and recreate mapped drives for users. The net result of the Replace action is to overwrite all existing settings associated with the mapped drive. If the drive mapping does not exist, then the Replace action creates a new drive mapping. Update Action The Update action will have a yellow triangle. Update will modify settings of an existing mapped drive for users. This action differs from Replace in that it only updates settings defined within the preference item. All other settings remain as configured on the mapped drive. If the