WMI and Network Adapters: 10

In episode 10 we saw how to renew the lease of a DHCP enabled NIC.  What about dropping the lease all together?

Lets go back to the NIC we are experimenting on.

Get-WmiObject -Class Win32_NetworkAdapterConfiguration -Filter "Index=’11′"  | gm -MemberType method

show us that we have a ReleaseDHCPLease method.

Get-WmiObject -Class Win32_NetworkAdapterConfiguration -Filter "Index=’11′" | select *dhcp

shows

DHCPLeaseExpires  : 20101009175810.000000+060
DHCPLeaseObtained : 20101008175810.000000+060

Get-WmiObject -Class Win32_NetworkAdapterConfiguration -Filter "Index=’11′" |

Invoke-WmiMethod -Name ReleaseDHCPLease

We can then try

Get-WmiObject -Class Win32_NetworkAdapterConfiguration -Filter "Index=’11′" | select *dhcp

which gives us

DHCPLeaseExpires  : 20101009175810.000000+060
DHCPLeaseObtained : 20101008175810.000000+060

Huh?   If you check your NIC the lease has been released but the information WMI holds doesn’t get updated. Woops.  Need to be careful of that one.

To generate a new lease we use the same method as episode 9

Get-WmiObject -Class Win32_NetworkAdapterConfiguration -Filter "Index=’11′" |

Invoke-WmiMethod -Name RenewDHCPLease

A return code of 0 indicates success and we can test the lease

Get-WmiObject -Class Win32_NetworkAdapterConfiguration -Filter "Index=’11′" | select *dhcp

DHCPLeaseExpires  : 20101009192845.000000+060
DHCPLeaseObtained : 20101008192845.000000+060