Changing IP Address Programmatically

D

Don Quixote

Hello,
I use the code below to change the IP of a machine :
________________________________________________________________________
Private Sub ChangeIP(NewIP, NewMask)
Dim NetworkAdapter, AdapterConfiguration 'Objects
Dim IPAddress, SubnetMask, Gateway, DNS, strGatewayMetric 'String Arrays
Dim RetVal, x 'Integers
Dim NICname As String
Dim tmpIP As String
tmpIP = GetIPAddress()

Dim NetAdapterCFG As SWbemObjectSet
Dim naCFG As SWbemObject

NICname = ""
For x = 1 To lvwInterfaces.ListItems.Count
If lvwInterfaces.ListItems(x).Checked = True Then NICname =
lvwInterfaces.ListItems(x).SubItems(6)
Next x
If NICname = "" Then Exit Sub

Set NetAdapterCFG =
GetObject("winmgmts:").InstancesOf("Win32_NetworkAdapterConfiguration")

For Each naCFG In NetAdapterCFG

If UCase(naCFG.ServiceName) = UCase(NICname) Then
IPAddress = Array(NewIP)
SubnetMask = Array(NewMask)
RetVal = naCFG.enableStatic(IPAddress, SubnetMask)

If Not RetVal = 0 Then
MsgBox "Failure assigning IP/Subnetmask." & vbCrLf &
"Possible duplicate IP address", vbCritical, "Warning"
IPAddress = Array(tmpIP)
RetVal = naCFG.enableStatic(IPAddress, SubnetMask)
msgBox "Failure assigning IP/Subnetmask."
Else
Debug.Print NewIP
End If
End If

Next

End Sub
__________________________________________________________________

It works fine and as far pinging goes or accessing the net, it works
alright. I do have problems accessing shares on the local network though.
Let's say my address is 192.168.10.80, and I can access other PCs on the
network, if I change thru the code above my IP to 192.168.10.81, I don't
access anymore the PCs. I can still ping them and I can go on the net. That
means my gateway and DNS still work, right ?
Needless to say, if I do the changes thru the Windows applet, everything
works fine.

Anybody has an idea of what is at play here ?

Thx a million.

Sal
 
J

Jim Carlock

The computer keeps a local cache of the DNS. Normally the way
to flush the local cache would be:

IPCONFIG /flushdns

on a win2k system or later.

Maybe someone knows how to get this done with an API call. The
following one seems to provide a means to flush the ARP cache.

'win2k or later
Declare Function FlushIpNetTable Lib "IPHLPAPI.dll" ( _
ByVal dwIfIndex As Long) As Long

Hope that helps.

--
Jim Carlock
Please post replies to newsgroup.

Hello,
I use the code below to change the IP of a machine :
________________________________________________________________________
Private Sub ChangeIP(NewIP, NewMask)
Dim NetworkAdapter, AdapterConfiguration 'Objects
Dim IPAddress, SubnetMask, Gateway, DNS, strGatewayMetric 'String Arrays
Dim RetVal, x 'Integers
Dim NICname As String
Dim tmpIP As String
tmpIP = GetIPAddress()

Dim NetAdapterCFG As SWbemObjectSet
Dim naCFG As SWbemObject

NICname = ""
For x = 1 To lvwInterfaces.ListItems.Count
If lvwInterfaces.ListItems(x).Checked = True Then NICname =
lvwInterfaces.ListItems(x).SubItems(6)
Next x
If NICname = "" Then Exit Sub

Set NetAdapterCFG =
GetObject("winmgmts:").InstancesOf("Win32_NetworkAdapterConfiguration")

For Each naCFG In NetAdapterCFG

If UCase(naCFG.ServiceName) = UCase(NICname) Then
IPAddress = Array(NewIP)
SubnetMask = Array(NewMask)
RetVal = naCFG.enableStatic(IPAddress, SubnetMask)

If Not RetVal = 0 Then
MsgBox "Failure assigning IP/Subnetmask." & vbCrLf &
"Possible duplicate IP address", vbCritical, "Warning"
IPAddress = Array(tmpIP)
RetVal = naCFG.enableStatic(IPAddress, SubnetMask)
msgBox "Failure assigning IP/Subnetmask."
Else
Debug.Print NewIP
End If
End If

Next

End Sub
__________________________________________________________________

It works fine and as far pinging goes or accessing the net, it works
alright. I do have problems accessing shares on the local network though.
Let's say my address is 192.168.10.80, and I can access other PCs on the
network, if I change thru the code above my IP to 192.168.10.81, I don't
access anymore the PCs. I can still ping them and I can go on the net. That
means my gateway and DNS still work, right ?
Needless to say, if I do the changes thru the Windows applet, everything
works fine.

Anybody has an idea of what is at play here ?

Thx a million.

Sal
 
P

Pegasus \(MVP\)

Don Quixote said:
Hello,
I use the code below to change the IP of a machine :
________________________________________________________________________
Private Sub ChangeIP(NewIP, NewMask)
Dim NetworkAdapter, AdapterConfiguration 'Objects
Dim IPAddress, SubnetMask, Gateway, DNS, strGatewayMetric 'String Arrays
Dim RetVal, x 'Integers
Dim NICname As String
Dim tmpIP As String
tmpIP = GetIPAddress()

Dim NetAdapterCFG As SWbemObjectSet
Dim naCFG As SWbemObject

NICname = ""
For x = 1 To lvwInterfaces.ListItems.Count
If lvwInterfaces.ListItems(x).Checked = True Then NICname =
lvwInterfaces.ListItems(x).SubItems(6)
Next x
If NICname = "" Then Exit Sub

Set NetAdapterCFG =
GetObject("winmgmts:").InstancesOf("Win32_NetworkAdapterConfiguration")

For Each naCFG In NetAdapterCFG

If UCase(naCFG.ServiceName) = UCase(NICname) Then
IPAddress = Array(NewIP)
SubnetMask = Array(NewMask)
RetVal = naCFG.enableStatic(IPAddress, SubnetMask)

If Not RetVal = 0 Then
MsgBox "Failure assigning IP/Subnetmask." & vbCrLf &
"Possible duplicate IP address", vbCritical, "Warning"
IPAddress = Array(tmpIP)
RetVal = naCFG.enableStatic(IPAddress, SubnetMask)
msgBox "Failure assigning IP/Subnetmask."
Else
Debug.Print NewIP
End If
End If

Next

End Sub
__________________________________________________________________

It works fine and as far pinging goes or accessing the net, it works
alright. I do have problems accessing shares on the local network though.
Let's say my address is 192.168.10.80, and I can access other PCs on the
network, if I change thru the code above my IP to 192.168.10.81, I don't
access anymore the PCs. I can still ping them and I can go on the net. That
means my gateway and DNS still work, right ?
Needless to say, if I do the changes thru the Windows applet, everything
works fine.

Anybody has an idea of what is at play here ?

Thx a million.

Sal
Click to expand...

You could do the same with a single line of code in a batch file:
netsh interface ip set address "Local Area Connection" static 125.187.7.56
255.0.0.0
It appears to take effect immediately.
 
D

Don Quixote

:
IPCONFIG /flushdns
Click to expand...

I had tried that already, but no luck. Since disabling and re-enabling the
NIC seems to fix the problems, I would settle for a way to reset the network
card from code (although I think it might be a kludge). Did not find
anything yet


Thx
 
D

Don Quixote

Pegasus (MVP) said:
You could do the same with a single line of code in a batch file:
netsh interface ip set address "Local Area Connection" static 125.187.7.56
255.0.0.0
It appears to take effect immediately.
Click to expand...

Thanks, but that was my way of doing it before, then I wanted to eliminate
the shelling out to an external command. Of course, if I do not find a
solution for my problem, I may be obliged to go back to the netsh method.

Sal
 

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