CreateIpNetEntry function (iphlpapi.h)

The CreateIpNetEntry function creates an Address Resolution Protocol (ARP) entry in the ARP table on the local computer.


  [in] PMIB_IPNETROW pArpEntry


[in] pArpEntry

A pointer to a MIB_IPNETROW structure that specifies information for the new entry. The caller must specify values for all members of this structure.

Return value

The function returns NO_ERROR (zero) if the function is successful.

If the function fails, the return value is one of the following error codes.

Return code Description
Access is denied. This error is returned on Windows Vista and Windows Server 2008 under several conditions that include the following: the user lacks the required administrative privileges on the local computer or the application is not running in an enhanced shell as the built-in Administrator (RunAs administrator).
An input parameter is invalid, no action was taken. This error is returned if the pArpEntry parameter is NULL, the dwPhysAddrLen member of MIB_IPNETROW is set to zero or a value greater than 8, the >dwAddr member of the MIB_IPNETROW structure is invalid, or one of the other members of the MIB_IPNETROW structure is invalid.
The IPv4 transport is not configured on the local computer.
Use FormatMessage to obtain the message string for the returned error.


To modify an existing ARP entry, use the SetIpNetEntry function. To retrieve the ARP table, call the GetIpNetTable function. To delete an existing ARP entry, call the DeleteIpNetEntry.

On Windows Vista and later, the CreateIpNetEntry function can only be called by a user logged on as a member of the Administrators group. If CreateIpNetEntry is called by a user that is not a member of the Administrators group, the function call will fail and ERROR_ACCESS_DENIED is returned.

The CreateIpNetEntry function can also fail because of user account control (UAC) on Windows Vista later. If an application that contains this function is executed by a user logged on as a member of the Administrators group other than the built-in Administrator, this call will fail unless the application has been marked in the manifest file with a requestedExecutionLevel set to requireAdministrator. If the application lacks this manifest file, a user logged on as a member of the Administrators group other than the built-in Administrator must then be executing the application in an enhanced shell as the built-in Administrator (RunAs administrator) for this function to succeed.

Note  On Windows NT 4.0 and Windows 2000 and later, this function executes a privileged operation. For this function to execute successfully, the caller must be logged on as a member of the Administrators group or the NetworkConfigurationOperators group.


Minimum supported client Windows 2000 Professional [desktop apps only]
Minimum supported server Windows 2000 Server [desktop apps only]
Target Platform Windows
Header iphlpapi.h
Library Iphlpapi.lib
DLL Iphlpapi.dll

See also






IP Helper Function Reference

IP Helper Start Page