# TEst-TCPTimeout
#
# Simple TCP-server to listen on a given port and send a Timestamp and Remote IP back with ascending delays
# Used to check Firewall, NAT Timeouts, Port reachability, externe IP-Address
#
# https://www.msxfaq.de/netzwerk/grundlagen/tcp_session_timeout.htm

param (
    $tcpport=25,
    $delay = (1,5,31,62,122,662,3600,7200,14400)
)

write-host "Start new Listner on port $($tcpport) "
$endpoint = new-object System.Net.IPEndPoint([system.net.ipaddress]::any, $tcpport)
$listener = new-object System.Net.Sockets.TcpListener $endpoint
$listener.start()   # warte auf eingehende Verbindungen 
                    # halte sie, bis sie von einem Accept abgeholt werden.

while (!$endscript) {                    
    write-host "---- Wait for connections on Port $($tcpport)(Blocking)"
    $connection = $listener.AcceptTcpClient() # Blockiert das Skript bis eine Verbindung ankommt

    $remoteip = "$($connection.Client.RemoteEndPoint.Address.IPAddressToString):$($connection.Client.RemoteEndPoint.Port.IPAddressToString)"
    write-host "New Connection from RemoteIP: $($remoteip)"
    $stream = $connection.GetStream()        # Binde Datenstrom

    [bool]$endscript = $false
    foreach ($step in $delay) {
        [string]$message = "Test-TCPConnection $($remoteip)  $((get-date).ToString(""o""))   Wait $($step) seconds`n`r"
        Write-Host "Sending: $($message)" -NoNewline
        $data = [text.Encoding]::Ascii.GetBytes($message)
        try {
            $stream.Write($data,0,$data.length) 
            $stream.Flush() 
        }
        catch {
            write-host "Problem sending message $($_.exception.message)" -ForegroundColor red
            break
        }
        for ($i = 0; $i -lt $step; $i++) {
            start-sleep -seconds 1
            Write-Progress -id 1 -Activity "Wait for Timeout" -SecondsRemaining ($step-$i) -PercentComplete ($i/$step*100) 
            if ([console]::KeyAvailable) {
                $keycode = [System.Console]::ReadKey($true) 
                if ($keycode.key -eq "X") {
                    Write-host "X Detected"
                    $endscript = $true
                    break  # leave current loop
                }
                else {
                    Write-host "Press X to stop"
                }
            }
        }
        Write-Progress -id 1 -Completed -Activity "Wait for Timeout"
        if ($endscript) {
            break # leave current loop
        }
    }
    Write-host "Closing Connection"
    $stream.close()   
    $connection.Close() # Verbindung beenden
}
$listener.stop()
write-host "Test-TCPTimeout - Done"