Function CheckIpv4(strIp As String)
    Dim regex As Variant
    Set regex = CreateObject("VBScript.RegExp")
    ' regex.global = True
    regex.Pattern = "\b((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)(\.|$)){4}\b"
    CheckIpv4 = regex.Test(strIp)
End Function