Powershell Convert NetTCPConnection or netstat To String

Question

Hello and thanks to anyone in advance who can help.

I am trying to write a powershell script that gets a list of all connections to a server containing a certain keyphrase and outputs the DNS names and corresponding IPs to a csv file.

I have run into some typing issues. This is my code for an attempt with NetTCPConnection:

# get remote addrs
$a = (Get-NetTCPConnection | Select-Object RemoteAddress)

# get IPs of valid addrs
Workflow Get-DNSNames([string[]]$IPAddresses){
    foreach -parallel ($IP in $IPAddresses | Select-Object -Unique){
        # $IP.ToString()
        [system.net.dns]::GetHostEntry($IP)).hostname
        try{
            @{$IP = $(([system.net.dns]::GetHostEntry($IP)).hostname)}
        }catch{
            @{$IP = "N/A"}
        }
    }
}

# output to txt
$List = Get-DNSNames -IPAddresses $a
$List | Out-File "C:\temp\getBAS\IPAddresses_Complete.txt"

And this is my attempt with netstat:

# get netstat output
$a = netstat

$b = $a[3..$a.count] | ConvertFrom-string | Select p4 | Where p4 -like "*52*"

# get IP and create name, IP pairs
$c = @()
foreach ($DNS in $b) {
    # name , IP
    $rowToAdd = New-Object psobject
    $name = $DNS
    $IP = [System.Net.Dns]::GetHostAddresses($DNS.ToString())
    $rowToAdd | Add-Member -Member NoteProperty -Name "Name" -value $name
    $rowToAdd | Add-Member -Member NoteProperty -Name "IP" -value $IP
    $c += $rowToAdd
}
$c

# output to csv
$final | Export-Csv -Path "C:\temp\getBAS\NetworkConnectionsBAS.csv" -NoTypeInformation

The problem with the first attempt is that the values from NetTCPConnection are objects, not strings, and strings are needed in the GetHost function. I could not figure out a way to convert each individual addr object to a string.

The problem with my second attempt is that I get a wacky csv output.

I am frankly stuck and would appreciate any help. Thanks

Answer 1

$a = (Get-NetTCPConnection | Select-Object RemoteAddress)

This is making $a an object with the RemoteAddress property in it, you aren't converting this to a string anywhere that I can see.

You can either change this line to

$a = (Get-NetTCPConnection | Select-Object -ExpandProperty RemoteAddress)

to get a String containing the value of RemoteAddress

or change

$List = Get-DNSNames -IPAddresses $a

to

$List = Get-DNSNames -IPAddresses "$($a.RemoteAddress)"

this will pull just the value from the property which should then be treated as a string.