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DNSSearchOrder--Nulling

I need to change from a static IP address to DHCP and turn DNS Search Order off on remote workstations. I have been able to use the following script to change the network configureation to DHCP.

$computers = get-content "C:\dns\computers.txt"
foreach($computer in $computers) {
if($computer -eq $null) {Write-Host"script has completed"} else
{
# Write-Host "Connect to $computers..."

Get-WmiObject -Class Win32_NetworkAdapterConfiguration -Filter IPEnabled=true -ComputerName $computer | ForEach-Object -Process {$_.InvokeMethod("EnableDHCP", $null)}
}
}

Now I am trying to use the following script to change the DNSServerSearchOrder to "Null". Actually what I would like to do is just turn the radial button on that states "obtain DNS server address automatically". The only way I have been able get the radial button to change is to be in DHCP mode and to null the DNSServerSearchOrder. The script I am currently working on to null the DNSServerSearchOrder is:

$computers = Get-Content "c:\DNS\computers.txt"
$DNSServers = "172.16.15.118", "172.16.15.119"
$NICs = Get-WmiObject -Class Win32_NetworkAdapterConfiguration -ComputerName "$computers" -Filter "DHCPEnabled=TRUE"

foreach($NIC in $NICs) {$NIC.SetDNSServerSearchOrder($Null)}

Ultimately, I would like to put the two scripts together in one process and run them at the same time. Bottom line is, I want to turn on DHCP and set "obtain DNS server address automatically" on if DHCP is enabled.

ExpertAssist

ASKER

I found some additional information that has helped with the script to "Null" the DNS Search Order. I had to create an empty array for the $DNSServers variable. Here is a script that works, however, I would like to consolidate the two scripts into one script. Also, I want to make sure that I do not end up nulling the DNS on workstations that have not yet been switched to DHCP. For instance, if I run the script and for some reason, it does not change the IP configuration to DHCP, I don't want the script to continue running and possibly change the DNS Server Search Order to "Null". Here is the script that I was able to get to work. I will still need to test to verify that it will work remotely and not just on my local workstation.

$computers = get-content "C:\DNS\computers.txt"
foreach($computer in $computers) {
if($computer -eq $null) {Write-Host"script has completed"} else
{
Write-Host "Connect to $computer..."
$DNSServers = @()
$NICs = Get-WmiObject -Class Win32_NetworkAdapterConfiguration -ComputerName $ComputerName -Filter "IPEnabled=TRUE"

foreach($NIC in $NICs) {$NIC.SetDNSServerSearchOrder($DNSServers) | out-null}
}}

ASKER CERTIFIED SOLUTION

Jamie McKillop

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ExpertAssist

ASKER

Hi jjmck,

I tried the script this morning with the following results. DHCP was enabled, but the DNS Server Search Order was not nulled. I received a message:

"You cannot call a method on a null-valued expression.
At line:7 char:45
+ $NIC.SetDNSServerSearchOrder <<<< ($DNSServers)
+ CategoryInfo : InvalidOperation: (SetDNSServerSearchOrder:Strin
g) [], RuntimeException
+ FullyQualifiedErrorId : InvokeMethodOnNull"

SOLUTION

ExpertAssist

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ASKER

I chose my answer to clarify that the script that jjmck wrote does what I asked, however, because of an additional issue that I discovered, I decided to run the scripts seperately. I also explained that reversing the order of the tasks performed in jjmck's script would resolve the issue that I discovered regarding the loss of connection when changing the DHCP.