How to check Network port access and display useful message? - powershell

Question

I was trying to check whether the port is opened or not using powershell like follows.
(new-object Net.Sockets.TcpClient).Connect("10.45.23.109", 443)
This method works , but the output is not user-friendly. It means if there are no errors then it has access. Is there any way to check for success and display some message like " Port 443 is operational"?

Answer 1

If you're running Windows 8/Windows Server 2012 or newer, you can use the Test-NetConnection command in PowerShell.
Ex:
Test-NetConnection -Port 53 -ComputerName LON-DC1

Answer 2

I improved Salselvaprabu's answer in several ways:
It is now a function - you can put in your powershell profile and use anytime you need
It can accept host as hostname or as ip address
No more exceptions if host or port unavaible - just text
Call it like this:
Test-Port example.com 999
Test-Port 192.168.0.1 80
function Test-Port($hostname, $port)
{
# This works no matter in which form we get $host - hostname or ip address
try {
$ip = [System.Net.Dns]::GetHostAddresses($hostname) |
select-object IPAddressToString -expandproperty IPAddressToString
if($ip.GetType().Name -eq "Object[]")
{
#If we have several ip's for that address, let's take first one
$ip = $ip[0]
}
} catch {
Write-Host "Possibly $hostname is wrong hostname or IP"
return
}
$t = New-Object Net.Sockets.TcpClient
# We use Try\Catch to remove exception info from console if we can't connect
try
{
$t.Connect($ip,$port)
} catch {}
if($t.Connected)
{
$t.Close()
$msg = "Port $port is operational"
}
else
{
$msg = "Port $port on $ip is closed, "
$msg += "You may need to contact your IT team to open it. "
}
Write-Host $msg
}

Answer 3

Actually Shay levy's answer is almost correct but i got an weird issue as i mentioned in his comment column. So i split the command into two lines and it works fine.
$Ipaddress= Read-Host "Enter the IP address:"
$Port= Read-host "Enter the port number to access:"
$t = New-Object Net.Sockets.TcpClient
$t.Connect($Ipaddress,$Port)
if($t.Connected)
{
"Port $Port is operational"
}
else
{
"Port $Port is closed, You may need to contact your IT team to open it. "
}

Answer 4

You can check if the Connected property is set to $true and display a friendly message:
$t = New-Object Net.Sockets.TcpClient "10.45.23.109", 443
if($t.Connected)
{
"Port 443 is operational"
}
else
{
"..."
}

Answer 5

With the latest versions of PowerShell, there is a new cmdlet, Test-NetConnection.
This cmdlet lets you, in effect, ping a port, like this:
Test-NetConnection -ComputerName <remote server> -Port nnnn
I know this is an old question, but if you hit this page (as I did) looking for this information, this addition may be helpful!

Answer 6

I tried to improve the suggestion from mshutov.
I added the option to use the output as an object.
function Test-Port($hostname, $port)
{
# This works no matter in which form we get $host - hostname or ip address
try {
$ip = [System.Net.Dns]::GetHostAddresses($hostname) |
select-object IPAddressToString -expandproperty IPAddressToString
if($ip.GetType().Name -eq "Object[]")
{
#If we have several ip's for that address, let's take first one
$ip = $ip[0]
}
} catch {
Write-Host "Possibly $hostname is wrong hostname or IP"
return
}
$t = New-Object Net.Sockets.TcpClient
# We use Try\Catch to remove exception info from console if we can't connect
try
{
$t.Connect($ip,$port)
} catch {}
if($t.Connected)
{
$t.Close()
$object = [pscustomobject] #{
Hostname = $hostname
IP = $IP
TCPPort = $port
GetResponse = $True }
Write-Output $object
}
else
{
$object = [pscustomobject] #{
Computername = $IP
TCPPort = $port
GetResponse = $False }
Write-Output $object
}
Write-Host $msg
}

Answer 7

If you are using older versions of Powershell where Test-NetConnection isn't available, here is a one-liner for hostname "my.hostname" and port "123":
$t = New-Object System.Net.Sockets.TcpClient 'my.hostname', 123; if($t.Connected) {"OK"}
Returns OK, or an error message.

Answer 8

Great answer by mshutov & Salselvaprabu. I needed something a little bit more robust, and that checked all IPAddresses that was provided instead of checking only the first one.
I also wanted to replicate some of the parameter names and functionality than the Test-Connection function.
This new function allows you to set a Count for the number of retries, and the Delay between each try. Enjoy!
function Test-Port {
[CmdletBinding()]
Param (
[string] $ComputerName,
[int] $Port,
[int] $Delay = 1,
[int] $Count = 3
)
function Test-TcpClient ($IPAddress, $Port) {
$TcpClient = New-Object Net.Sockets.TcpClient
Try { $TcpClient.Connect($IPAddress, $Port) } Catch {}
If ($TcpClient.Connected) { $TcpClient.Close(); Return $True }
Return $False
}
function Invoke-Test ($ComputerName, $Port) {
Try { [array]$IPAddress = [System.Net.Dns]::GetHostAddresses($ComputerName) | Select-Object -Expand IPAddressToString }
Catch { Return $False }
[array]$Results = $IPAddress | % { Test-TcpClient -IPAddress $_ -Port $Port }
If ($Results -contains $True) { Return $True } Else { Return $False }
}
for ($i = 1; ((Invoke-Test -ComputerName $ComputerName -Port $Port) -ne $True); $i++)
{
if ($i -ge $Count) {
Write-Warning "Timed out while waiting for port $Port to be open on $ComputerName!"
Return $false
}
Write-Warning "Port $Port not open, retrying..."
Sleep $Delay
}
Return $true
}

Answer 9

boiled this down to a one liner sets the variable "$port389Open" to True or false - its fast and easy to replicate for a list of ports
try{$socket = New-Object Net.Sockets.TcpClient($ipAddress,389);if($socket -eq $null){$Port389Open = $false}else{Port389Open = $true;$socket.close()}}catch{Port389Open = $false}
If you want ot go really crazy you can return the an entire array-
Function StdPorts($ip){
$rst = "" | select IP,Port547Open,Port135Open,Port3389Open,Port389Open,Port53Open
$rst.IP = $Ip
try{$socket = New-Object Net.Sockets.TcpClient($ip,389);if($socket -eq $null){$rst.Port389Open = $false}else{$rst.Port389Open = $true;$socket.close();$ipscore++}}catch{$rst.Port389Open = $false}
try{$socket = New-Object Net.Sockets.TcpClient($ip,53);if($socket -eq $null){$rst.Port53Open = $false}else{$rst.Port53Open = $true;$socket.close();$ipscore++}}catch{$rst.Port53Open = $false}
try{$socket = New-Object Net.Sockets.TcpClient($ip,3389);if($socket -eq $null){$rst.Port3389Open = $false}else{$rst.Port3389Open = $true;$socket.close();$ipscore++}}catch{$rst.Port3389Open = $false}
try{$socket = New-Object Net.Sockets.TcpClient($ip,547);if($socket -eq $null){$rst.Port547Open = $false}else{$rst.Port547Open = $true;$socket.close();$ipscore++}}catch{$rst.Port547Open = $false}
try{$socket = New-Object Net.Sockets.TcpClient($ip,135);if($socket -eq $null){$rst.Port135Open = $false}else{$rst.Port135Open = $true;$socket.close();$SkipWMI = $False;$ipscore++}}catch{$rst.Port135Open = $false}
Return $rst
}

Answer 10

When scanning closed port it becomes unresponsive for long time. It seems to be quicker when resolving fqdn to ip like:
[System.Net.Dns]::GetHostAddresses("www.msn.com").IPAddressToString