Mine

Imports System.Net.Sockets.TcpListener
Imports System.Net.Sockets
Imports System.Net

Public Class Form1
    Dim Listener As TcpListener
    Dim LocalIP As IPAddress = Dns.GetHostEntry("localhost").AddressList(0)

    Private Sub btnListen_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnListen.Click
        Listener = New TcpListener(LocalIP, 5081)
        Listener.Start()
        lblStatus.ForeColor = Color.Green
        lblStatus.Text = "Server Listening...."
        btnListen.Enabled = False
        btnStop.Enabled = True
    End Sub

    Private Sub btnStop_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnStop.Click
        Listener.Stop()
        lblStatus.ForeColor = Color.Red
        lblStatus.Text = "Server Stopped"
        btnListen.Enabled = True
        btnStop.Enabled = False
    End Sub
End Class