While ping is excellent for basic network connectivity checks (ICMP), it doesn't help when you need to verify TCP port availability. This becomes crucial when:

• Monitoring web servers (port 80/443)
• Checking database connectivity (3306, 5432, etc.)
• Verifying application-specific ports
• Testing firewall rules

Windows provides several built-in utilities for port testing:

Test-NetConnection -ComputerName 192.168.1.1 -Port 8080

For continuous monitoring in PowerShell:

while ($true) {
    $result = Test-NetConnection -ComputerName 192.168.1.1 -Port 8080 -InformationLevel Quiet
    "$(Get-Date -Format 'yyyy-MM-dd HH:mm:ss') - Port status: $result" | Out-File -Append port_monitor.log
    Start-Sleep -Seconds 5
}

While not ideal for continuous monitoring, telnet provides quick manual checks:

telnet 192.168.1.1 3389

For more robust monitoring, consider:

# Using Nmap (requires installation)
nmap -p 80 -Pn 192.168.1.1

# Continuous monitoring with Nmap
while true; do
    nmap -p 80 -Pn 192.168.1.1 | find "80/tcp"
    timeout /t 5 > nul
done

For enterprise-grade monitoring:

$port = 8080
$server = "192.168.1.1"
$timeout = 1000 # milliseconds
$logPath = "C:\logs\port_monitor.csv"

while ($true) {
    $tcpClient = New-Object System.Net.Sockets.TcpClient
    $connectTask = $tcpClient.ConnectAsync($server, $port)
    
    if ($connectTask.Wait($timeout)) {
        $status = if ($tcpClient.Connected) { "Open" } else { "Closed" }
    } else {
        $status = "Timeout"
    }
    
    $timestamp = Get-Date -Format "yyyy-MM-dd HH:mm:ss"
    "$timestamp,$server,$port,$status" | Out-File -Append -FilePath $logPath
    
    $tcpClient.Dispose()
    Start-Sleep -Seconds 10
}

For comprehensive monitoring:

1. Open perfmon.exe
2. Add new Data Collector Set
3. Select "TCPv4" or "TCPv6" counters
4. Monitor "Connections Established" and "Connection Failures"

After collecting data, you can analyze it with:

# PowerShell to visualize recent data
Import-Csv $logPath | 
Where-Object { $_.Timestamp -gt (Get-Date).AddHours(-24) } |
Group-Object Status |
Select-Object Count,Name |
Sort-Object Count -Descending

While the ping command is excellent for basic ICMP-based host availability checks, it falls short when we need to verify TCP/UDP port availability. Many production environments require continuous monitoring of specific service ports (like 80, 443, 3389, etc.) rather than just host reachability.

Windows provides several built-in alternatives:

1. Test-NetConnection (PowerShell):
Test-NetConnection 192.168.1.1 -Port 80 -InformationLevel Detailed

2. PortQry (Microsoft's dedicated tool):
portqry -n 192.168.1.1 -e 80 -nr

For persistent monitoring like your ping -t example, consider these approaches:

PowerShell Loop Method

while($true) {
    $result = Test-NetConnection 192.168.1.1 -Port 3389
    if($result.TcpTestSucceeded) {
        "$(Get-Date -Format 'yyyy-MM-dd HH:mm:ss') - Port OPEN" | Out-File port_monitor.log -Append
    }
    else {
        "$(Get-Date -Format 'yyyy-MM-dd HH:mm:ss') - Port CLOSED" | Out-File port_monitor.log -Append
    }
    Start-Sleep -Seconds 5
}

Nmap for Advanced Scanning

The popular Nmap tool offers richer functionality:

nmap -p 80 --open -T4 192.168.1.1 -oG - | find "80/open"

When dealing with firewalls that block ICMP, TCP-based checks are essential. The PowerShell method above works through firewalls when proper exceptions exist.

• TCPing: Lightweight console tool mimicking ping behavior for ports
• PortMon: Graphical port monitoring utility
• PsPing: Part of Sysinternals suite with advanced capabilities

For production environments, consider dedicated monitoring tools like:

• PRTG Network Monitor
• SolarWinds Port Monitor
• Nagios with check_tcp plugin