# Troubleshooting network applications with PowerShell and tnc

> Test whether a website, mail server or database port is reachable from Windows using PowerShell's Test-NetConnection.

Source: https://helpcenter.ruachost.com/developers/networking/troubleshooting-network-applications-with-powershell-and-tnc/

When a network application (such as a website, mail server, or database) is not responding, you can use **PowerShell** to test connectivity. Test-NetConnection cmdlet (alias: tnc) is a powerful built-in tool for diagnosing network issues.

## What Is `Test-NetConnection`?

- Test-NetConnection(or tnc) is a PowerShell cmdlet available in Windows 8.1, Windows Server 2012 R2, and later.
- It combines the functionality of **ping**, **traceroute**, and **port testing** into one command.
- It helps determine if a host is reachable and whether a specific service port is open.

## Common Uses of tnc

### 1. Basic Connectivity Test

Check if a host is reachable:

```
Powershell

tnc example.com
```

- Returns ping results, IP address, and basic connectivity status.

### 2. Test a Specific Port

Check if a service port is open (e.g., HTTPS on port 443):

```
Powershell

tnc example.com -Port 443
```

- Useful for testing web servers, mail servers, or custom applications.

### 3. Trace Route to a Host

See the path packets take to reach the destination:

```
Powershell

tnc example.com -TraceRoute
```

- Helps identify where along the route packets are being dropped or delayed.

### 4. Test with Detailed Output

Get extended diagnostic information:

```
Powershell

tnc example.com -Port 25 -InformationLevel Detailed
```

- Useful for troubleshooting mail servers (SMTP on port 25).

## When to Use tnc

- Website not loading → Test port **80** (HTTP) or **443** (HTTPS).
- Email not sending → Test ports **25**, **465**, or **587** (SMTP).
- Database connection issues → Test the database port (e.g., **3306** for MySQL, **1433** for SQL Server).
- General connectivity issues → Use -TraceRoute to see where the connection fails.