Powershell function with no errors and no results

Question

I would like to scan the batch of my local networks to find all standalone Wi-Fi AP. I'm going to archive this by checking the TCP/80 port. I have 89 networks in the text file. My script is below. The script seems to run but I get no output either to the screen or to any file. I would be very appreciative if someone could tell me what's wrong.

#PSVersion 7.1.3 #-----------------------------------------

function Test-Port() {
    [CmdletBinding()]
    param (
        [Parameter(ValueFromPipeline = $true, Mandatory = $true)]
        [Alias('tp')]
        [string[]]$network,
        [int]$port = 80
    )
    #Begin { Write-Verbose "Scanning network $network"}
    Process {
        1..254 | ForEach-Object -Parallel -ThrottleLimit 10 {
            $ip = "$network.$_"
            If ($(Test-netConnection –ComputerName $ip -Port $port -ErrorAction SilentlyContinue).TcpTestSucceeded ) {
                Write-Output "$ip port $port open" | Out-File "C:\tmp\$network.txt"
            }   
        }
    }
}

[string[]]$lans = Get-Content -Path "C:\tmp\lans.txt"
   
#$lans | Test-Port
Test-Port -network $lans

====== Even this doesn't work with -Parallel. It just doesn't see the $n.

[string[]]$networks = Get-Content -Path "C:\tmp\lans.txt"
[string[]]$a = 1..50
foreach ($n in $networks) {  
     ForEach-Object -InputObject ($a) -parallel {
         write-output $n
     }  }

And it works fine without -parallel

Do you know the function works? Is the variable $lans populated? — Alex_P
– Alex_P, Commented Jul 23, 2021 at 16:08
so ... if you strip out all the function stuff and just run the core code ... where does it stop outputting info? — Lee_Dailey
– Lee_Dailey, Commented Jul 23, 2021 at 16:09
@Alex_P Yes, $lans populated. i.e. ... 192.168.3 10.2.18 10.2.30 10.2.11 10.2.18 10.222.176 ...etc — The author of the Comment
– The author of the Comment, Commented Jul 23, 2021 at 18:04
@Lee_Dailey it works fine out of function. And moreover, it works fine inside the function if I remove -Parallel -ThrottleLimit 10 — The author of the Comment
– The author of the Comment, Commented Jul 23, 2021 at 18:28
Outside the function. And without -Parallel. Just this part: ----- [string[]]$networks = Get-Content -Path "C:\tmp\lans.txt" foreach ($net in $networks) { 1..254 | ForEach-Object { $ip = "$net.$_" If ($(Test-netConnection –ComputerName $ip -Port 80 -ErrorAction SilentlyContinue).TcpTestSucceeded ) { Write-Output "$ip port $port open" | Out-File "C:\tmp\$net.txt" -Append } } } ----- Works fine. But it's very slow because of the quantity of IP addresses. If I add -Parallel I see WARNING: Name resolution of .88 failed — The author of the Comment
– The author of the Comment, Commented Jul 23, 2021 at 18:45

Mathias R. Jessen · Accepted Answer · 2021-07-23 16:15:50Z

3

$network is a string array, you need to loop over it :)

function Test-Port() {
    [CmdletBinding()]
    param (
        [Parameter(ValueFromPipeline = $true, Mandatory = $true)]
        [Alias('tp')]
        [string[]]$network,
        [int]$port = 80
    )
    #Begin { Write-Verbose "Scanning network $network"}
    Process {
        foreach($net in $network){
            1..254 | ForEach-Object -Parallel -ThrottleLimit 10 {
                $ip = "$net.$_"
                If ($(Test-netConnection –ComputerName $ip -Port $port -ErrorAction SilentlyContinue).TcpTestSucceeded ) {
                    Write-Output "$ip port $port open" | Out-File "C:\tmp\$network.txt"
                }   
            }
        }
    }
}

answered Jul 23, 2021 at 16:15

Mathias R. Jessen

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2 Comments

The author of the Comment Over a year ago

Of course :). You're right. I fixed this part. And change Out-File to Out-File "C:\tmp\$net.txt" -Append. BUT. It doesn't work anyway. Maybe I'm blind, but I don't see the mistake....

The author of the Comment Over a year ago

So, it works fine after I removed -Parallel -ThrottleLimit 10 part. What a pity.

The author of the Comment · Accepted Answer · 2021-07-23 20:58:48Z

1

Finally! The trick is $using

$ip = "$($using:net).$_"

function Test-Port() {
    [CmdletBinding()]
    param (
        [Parameter(ValueFromPipeline = $true, Mandatory = $true)]
        [Alias('tp')]
        [string[]]$networks
    )
    Process {
        foreach ($net in $networks) {  
            1..254 | ForEach-Object -Parallel {
                $ip = "$($using:net).$_"
                If ($((Test-NetConnection –ComputerName $ip -Port 80 -InformationLevel Quiet).TcpTestSucceeded)) {
                Write-Output "$ip port 80 is open"  | Out-File "C:\tmp\$($using:net).txt" -Append
                } 
            }  
        }
    }
}


[string[]]$networks = Get-Content -Path "C:\tmp\lans.txt"

Test-Port -networks $networks

It works. Thanks to all for your help, guys!

edited Jul 23, 2021 at 20:58

answered Jul 23, 2021 at 20:32

The author of the Comment

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1 Comment

Abraham Zinala Over a year ago

Please mark Mathias post as the answer if he answered your request.

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Powershell function with no errors and no results

====== Even this doesn't work with -Parallel. It just doesn't see the $n.

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$ip = "$($using:net).$_"

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====== Even this doesn't work with -Parallel. It just doesn't see the $n.

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$ip = "$($using:net).$_"

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