What is this line of code doing?

[!NoItAll]

Hi:
If someone wouldn't mind helping me out. I have some code from an example from reachmail.net. It was in C# but I've refactored it to vb.net. But, I'm ignorant and although I can follow all of the code (it's very simple code) - I have no idea what one line is doing or why it is there...
It's a little embarassing...
Here's the line

        System.Net.ServicePointManager.ServerCertificateValidationCallback = Function(s, ce, ca, p) True

and here is the context...

Imports System.Net.Mail

Public Class SendViaES
    Public WithEvents client As New System.Net.Mail.SmtpClient()
    Private bSent As Boolean = False

    Public Sub easyTest()
        bSent = False
        Dim smtp_host As String = "ssrs.reachmail.net"
        Dim smtp_port As Integer = 25
        Dim user As String = "username"
        Dim pswd As String = "Password"
        Dim rcpt As String = "name@domain.com"
        Dim from As String = "name@domain.com"
        Dim Subject As String = "Brown Fox"
        Dim Body As String = "The quick brown fox jumped over the lazy dogs back."

        System.Net.ServicePointManager.ServerCertificateValidationCallback = Function(s, ce, ca, p) True

        Dim Mail As New System.Net.Mail.MailMessage(from, rcpt, Subject, Body)

        client.Host = smtp_host
        client.Credentials = New System.Net.NetworkCredential(user, pswd)
        client.EnableSsl = True
        client.Port = smtp_port
        Dim userstate As String = "test Message"
        Try
            client.SendAsync(Mail, userstate)
            Do Until bSent = True
                Application.DoEvents()
            Loop

        Catch ex As Exception
            MsgBox(ex.Message, MsgBoxStyle.OkOnly)
        End Try
    End Sub

    Public Sub ClientResponse(ByVal sender As Object, ByVal e As System.ComponentModel.AsyncCompletedEventArgs) Handles client.SendCompleted
        If e.Cancelled Then
            MsgBox("Server cancelled!")
        Else
            If IsNothing(e.Error) Then
                MsgBox("Email Sent!")
            Else
                MsgBox(e.Error.ToString)
            End If
        End If
        bSent = True
    End Sub
End Class

Any guidance and explanation would be very much appreciated!

By the way - no, I am not building a spammer app - I am building an SMTP connection inside an application so that a major failure can send an email to engineers responsible for the task the app does.

!NoItAl (the ! says it all)