vb 验证ip地址

ip地址的规则是什么？~~~

新建Command1、Text1
text1输入ip的
Public Function Valid_IP(IP As String) As Boolean
Dim i As Integer
Dim dot_count As Integer
Dim test_octet As String
Dim byte_check
IP = Trim$(IP)
If Len(IP) < 8 Then '判断IP地址的位数是否足够
Valid_IP = False
'如果不够位数，显示错误信息
MsgBox IP & " 不是有效的IP地址", , "IP地址检测"
Exit Function
End If
i = 1
dot_count = 0
For i = 1 To Len(IP)
If Mid$(IP, i, 1) = "." Then
'累计小数点的数目
dot_count = dot_count + 1
test_octet = ""
If i = Len(IP) Then
Valid_IP = False
'显示错误信息
MsgBox IP & " 不是有效的IP地址", , "IP地址检测"
Exit Function
End If
Else
te