Figuring out which VMNIC is assigned to what physical NIC port

esxcfg-nics -l

How to find running processes and their port number

Source

The netstat command line utility displays protocol statistics and current TCP/IP network connections. If we want to display the associated process identifier (PID) of each process we add the -o parameter.

To filter the result we need to pipe to the Find utility and again, the result is text!. In PowerShell we can get the same information with the following command, however the process PID is missing and the connections in LISTENING state are not included by default.

PS > [System.Net.NetworkInformation.IPGlobalProperties]::GetIPGlobalProperties().GetActiveTcpConnections()

With the Get-NetworkStatistics function we can get the same information but each returned connection is an object. Get-NetworkStatistics parses only TCP/UDP connections (entries that starts with '[::' are ignored). Each connection is divided into two columns. For example, if the 'Local Address' column has a value of '0.0.0.0:80' the IP address will be shown in the LocalAddress property (e.g 0.0.0.0)  and the port number in the LocalPort property (e.g 80). The name of each process is also added to the result. This should make filtering much more easier when we pipe the result to the Where-Object cmdlet, allowing us to filter on any property of a connection.

UPDATE: Added support for IPv6 connections. @xcud and surveyor, thanks for the input!

function Get-NetworkStatistics
{
    $properties = 'Protocol','LocalAddress','LocalPort'
    $properties += 'RemoteAddress','RemotePort','State','ProcessName','PID'

    netstat -ano | Select-String -Pattern '\s+(TCP|UDP)' | ForEach-Object {

        $item = $_.line.split(" ",[System.StringSplitOptions]::RemoveEmptyEntries)

        if($item[1] -notmatch '^\[::')
        {           
            if (($la = $item[1] -as [ipaddress]).AddressFamily -eq 'InterNetworkV6')
            {
               $localAddress = $la.IPAddressToString
               $localPort = $item[1].split('\]:')[-1]
            }
            else
            {
                $localAddress = $item[1].split(':')[0]
                $localPort = $item[1].split(':')[-1]
            } 

            if (($ra = $item[2] -as [ipaddress]).AddressFamily -eq 'InterNetworkV6')
            {
               $remoteAddress = $ra.IPAddressToString
               $remotePort = $item[2].split('\]:')[-1]
            }
            else
            {
               $remoteAddress = $item[2].split(':')[0]
               $remotePort = $item[2].split(':')[-1]
            } 

            New-Object PSObject -Property @{
                PID = $item[-1]
                ProcessName = (Get-Process -Id $item[-1] -ErrorAction SilentlyContinue).Name
                Protocol = $item[0]
                LocalAddress = $localAddress
                LocalPort = $localPort
                RemoteAddress =$remoteAddress
                RemotePort = $remotePort
                State = if($item[0] -eq 'tcp') {$item[3]} else {$null}
            } | Select-Object -Property $properties
        }
    }
}

Get-NetworkStatistics | Format-Table 

To get all processes running on a local port 80:

Or find a connection information by filtering on ProcessName:

Zenmap (Nmap Gui)–Network Scanner

http://nmap.org/zenmap/

Zenmap is the official Nmap Security Scanner GUI. It is a multi-platform (Linux, Windows, Mac OS X, BSD, etc.) free and open source application which aims to make Nmap easy for beginners to use while providing advanced features for experienced Nmap users. Frequently used scans can be saved as profiles to make them easy to run repeatedly. A command creator allows interactive creation of Nmap command lines. Scan results can be saved and viewed later. Saved scan results can be compared with one another to see how they differ. The results of recent scans are stored in a searchable database.

You can download Zenmap (often packaged with Nmap itself) from the Nmap download page. Zenmap is quite intuitive, but you can learn more about using it from the Zenmap User's Guide or check out the Zenmap man page for some quick reference information.

Here are some Zenmap action shots (click for full res):