Powershell: Filtering server list by the 2nd octet of the IP address

Question

I am trying to go through a list of servers for further querying via WMI. Unfortunately, if the scripts hits a server that cannot connect via WMI, it takes a long time before timing out.

These are generally servers in our DMZ, and allocated a specific address in the 2nd octet of the IP address, .92 for example. So I am looking to filter out these servers as the first step in my query, so it can be ignore in any further WMI queries.

I have found many examples on how to do this, and again, I cannot use WMI methods as this defeats the object (eg: Get-WmiObject Win32_NetworkAdapterConfiguration).

In the example below, the server "SERVER" has an IP of 192.9.4.1 and I want to filter out all servers with ".9" in the second octet. so I use a simple Test-Connection cmdlet, and aim to split the result. Before I can split it, the result of the Test-Connection is:

$IP4Address = Test-Connection _Computer SERVER -Count 1 | Select IPV4Address

@{IPV4Address=192.9.4.1}

Which means that I need to count 19 chars from the beginning to get my "9". IPV4Address

  $Octet = $IP4Address -split ("") 
  If ($Octet[19] -eq '9') 
    {write-host "In DMZ"} 
  Else
    {write-host "Not in DMZ"}

Before you ask, I did try -split (".") but this doesn't seem to take any effect.

So why does the result come out like @{IPV4Address=192.9.4.1}? Is there a better solution?

Answer 1

To only get the value of the IPV4Address property you will have to expand it:

$IP4Address = Test-Connection -Computer SERVER -Count 1 |
    Select-Object -ExpandProperty IPV4Address

Then you can use the .Split() method:

if($IPV4Address.Split(".")[1] -eq "9") {
  "In DMZ"
} else {
  "Not in DMZ"
}

PS : I usually use -Count 2 rather than -Count 1