Obtain Guest Subnet Mask

[jaguar5150]

Hello,

I've been up and down the internet and cannot seem to find an answer to this.

I'm trying to script output to include a Guest VM's IP address and its Subnet Mask.  I cannot seem to find any command that will present it without having to provide an account to the VM (Get-VMGuestNetworkInterface).  Isn't VMtools aware of the IPaddress and netmask?  Maybe this is so simple I'm overlooking something.

I'm looking for something like this:  Get-Cluster "<cluster>" | Get-VM | Select Name, {$_.Guest.IPAddress}, {$_.ExtensionData.Summary.Guest.Subnet}

Obviously "Guest.Subnet" isn't a valid parameter, but is there something that would work in its place?

Thanks in advance!

[LucD]

The subnet mask is not directly available, but the prefixlength is :smileycool:

Try something like this

$vm = Get-VM MyVM
$vm.ExtensionData.Guest.Net | Select @{N="VM";E={$vm.Name}},MacAddress,Network,
    @{N="DHCP";E={$_.IpConfig.Dhcp.Ipv4.Enable}},
    @{N="IP";E={$_.IpAddress[0]}},
    @{N="Subnet Mask";E={
        $dec = [Convert]::ToUInt32($(("1" * $_.IpConfig.IpAddress[0].PrefixLength).PadRight(32, "0")), 2)
        $DottedIP = $( For ($i = 3; $i -gt -1; $i--) {
          $Remainder = $dec % [Math]::Pow(256, $i)
          ($dec - $Remainder) / [Math]::Pow(256, $i)
          $dec = $Remainder
         } )
        [String]::Join('.', $DottedIP) 
    }}

Note that this only handles VMs with 1 NIC and an IPv4 address.

For multiple NICs the code needs to be adapted.

[jaguar5150]

Wow, nice one.  I think it's safe to say I would not have figured that out.  Worked great for one VM!  If I may ask for one small modification - I would like to run this against all VMs in a cluster (or group of cluster).  Is that possible?

Thanks a ton!

[LucD]

Sure, something like this should do the trick

foreach($vm in (Get-Cluster | Get-VM)){
    $vm.ExtensionData.Guest.Net | Select @{N="VM";E={$vm.Name}},MacAddress,Network,
    @{N="DHCP";E={$_.IpConfig.Dhcp.Ipv4.Enable}},
    @{N="IP";E={$_.IpAddress[0]}},
    @{N="Subnet Mask";E={
            $dec = [Convert]::ToUInt32($(("1" * $_.IpConfig.IpAddress[0].PrefixLength).PadRight(32, "0")), 2)
            $DottedIP = $( For ($i = 3; $i -gt -1; $i--) {
                    $Remainder = $dec % [Math]::Pow(256, $i)
                    (                        $dec - $Remainder) / [Math]::Pow(256, $i)
                    $dec = $Remainder
                } )
            [String]::Join('.', $DottedIP) 
        }}
}

[jaguar5150]

Thanks again.  And my apologies, I thought I would be able to figure this one out on my own, but I cannot seem to get it to export to .csv.  If I pipe in Export-CSV on the end of it all, it throws an error about an empty pipe element.

Any ideas there?

[LucD · Accepted solution]

That is because the ForEach doesn't place any objects in the pipeline.

A trick to avoid this, is to do the complete script in "call" block (the & operator), and then pipe that to the Export-Csv.

Something like this

&{foreach($vm in (Get-Cluster | Get-VM)){
    $vm.ExtensionData.Guest.Net | Select @{N="VM";E={$vm.Name}},MacAddress,Network,
    @{N="DHCP";E={$_.IpConfig.Dhcp.Ipv4.Enable}},
    @{N="IP";E={$_.IpAddress[0]}},
    @{N="Subnet Mask";E={
            $dec = [Convert]::ToUInt32($(("1" * $_.IpConfig.IpAddress[0].PrefixLength).PadRight(32, "0")), 2)
            $DottedIP = $( For ($i = 3; $i -gt -1; $i--) {
                    $Remainder = $dec % [Math]::Pow(256, $i)
                    (                        $dec - $Remainder) / [Math]::Pow(256, $i)
                    $dec = $Remainder
                } )
            [String]::Join('.', $DottedIP) 
        }}
}} | Export-Csv -Path report.csv -NoTypeInformation -UseCulture

[jaguar5150]

Thank you very much!  This is perfect!

[DomusIT]

Thanks for a VERY useful script! - a bit of editing and here is a script version that lists ALL VM's (not just the ones that are included in clusters) - also inluded secondary IP's and MASK's so that IPv4 and IPv6 are shown:

foreach($vm in (Get-VM)){

    $vm.ExtensionData.Guest.Net | Select @{N="VM";E={$vm.Name}},MacAddress,Network,

    @{N="DHCP";E={$_.IpConfig.Dhcp.Ipv4.Enable}},

    @{N="IP-1";E={$_.IpAddress[0]}},

    @{N="Subnet Mask-1";E={

            $dec = [Convert]::ToUInt32($(("1" * $_.IpConfig.IpAddress[0].PrefixLength).PadRight(32, "0")), 2)

            $DottedIP = $( For ($i = 3; $i -gt -1; $i--) {

                    $Remainder = $dec % [Math]::Pow(256, $i)

                    (                        $dec - $Remainder) / [Math]::Pow(256, $i)

                    $dec = $Remainder

                } )

            [String]::Join('.', $DottedIP)

        }},

    @{N="IP-2";E={$_.IpAddress[1]}},

    @{N="Subnet Mask-2";E={

            $dec = [Convert]::ToUInt32($(("1" * $_.IpConfig.IpAddress[1].PrefixLength).PadRight(32, "0")), 2)

            $DottedIP = $( For ($i = 3; $i -gt -1; $i--) {

                    $Remainder = $dec % [Math]::Pow(256, $i)

                    (                        $dec - $Remainder) / [Math]::Pow(256, $i)

                    $dec = $Remainder

                } )

            [String]::Join('.', $DottedIP)

        }}

}

- Erkka Hakkarainen

[MRoushdy]

LuCD, You always impress me. Thanks a lot, this script saved us a lot of time.

[bikashyadav]

How do we add the gateway here  ? Tried but its giving irrelevant info.