Need vbscript to ping and switch between gateway

[Kidscorpion]

Hi All,

I am newbie to this forum.

I need a script to ping gateway and if gateway is down, change default gateway setting in TCP/IP property and switch to new gateway.

I think it can do with vbscript. But i don't know how write.

Could someone help me or guide me?

Thanks you very much for your time and sharing knowledge.

Edited June 19, 2008 by Kidscorpion

[CoffeeFiend]

That is both a simple and a complicated problem at once.

Ping'ing is trivial (you use the Win32_PingStatus WMI class, or if you have older OS'es i.e. win2k and below, then you have have to call ping.exe and parse the text output).

As for the gateways, you can enumerate them (string DefaultIPGateway[]; property of the class), and set it with the SetGateways method of the same class. All good so far.

Now the hard part: how do you determine which NIC to use it against if it has more than one? (this box has 4)

A quick and dirty script (5 minute job, could be a lot nicer), that works more or less blindly, and tries to set it on all NICs:

On Error Resume Next
strComputer = "."
Dim arrGateways(0)
arrGateways(0) = "192.168.1.1"
Set objWMIService = GetObject("winmgmts:{impersonationLevel=impersonate}!\\" & strComputer & "\root\cimv2")
Set colNicConfigs = objWMIService.ExecQuery ("SELECT * FROM Win32_NetworkAdapterConfiguration WHERE IPEnabled = True")
For Each objNicConfig In colNicConfigs
  If Not IsNull(objNicConfig.DefaultIPGateway) Then
	strDefaultIPGateway = Join(objNicConfig.DefaultIPGateway)
	Set colPings = objWMIService.ExecQuery ("SELECT * FROM Win32_PingStatus WHERE Address = '" & strDefaultIPGateway & "'")
	For Each objPing in colPings
	  If objPing.StatusCode <> 0 Then 
		objNicConfig.SetGateways(arrGateways)
	  End If
	Next
  Else
	'gateway is not set! uncomment next line to force set it
	'objNicConfig.SetGateways(arrGateways)
  End If
Next

Change the gateway IP from 192.168.1.1 to whatever you need to set it to. You can also make the array bigger, and add more values to it if you need more than one gateway.

Anything else just ask.

[Kidscorpion]

HI Crahak,

Thanks a lot for your help. I will try.

All pc are WinXp with one NIC. We have only two gateways for this branch. If one down, we want to switch to another one.

Cheers....!

[CoffeeFiend]

All pc are WinXp with one NIC. We have only two gateways for this branch. If one down, we want to switch to another one.

Then the script should work.

You could try having both Gateways there in the config though, like such:

Dim arrGateways(1)
arrGateways(0) = "192.168.1.1"
arrGateways(1) = "192.168.1.2"

Where 192.168.1.1 and 192.168.1.2 are the addresses of both your gateways, but I'm not 100% sure if windows will auto-switchover if one fails (we don't have redundant gateways, never tried, or looked into it much for that matter). You might wanna look at MS Article ID's 128978 and 171564.

[Kidscorpion]

Dear Crahak,

What i am trying to do is that i want to ping from client PC in every minute to default Router( we have 2 routers) and if the link is down, it will need to change default gateway to another router.

I had tried manually with Netsh command to change default gateway setting in TCP/IP properties.

Currently, if the link is down, user need to manually run this Netsh batch file to change default gateway.

After that their pc can switch to another default gateway.

I think it will ok with vbscript for auto ping and change default gateway setting.

But the problem is that i have a little knowledge in vbscript.

Thanks for your time and knowledge sharing.

[Mijzelf]

What about a batchfile?

@echo off
	  set GATEWAY1=192.168.1.1
	  set GATEWAY2=192.168.1.2

	  set CURRENTGATEWAY=%GATEWAY2%

	  :CheckGateway
	  ping %CURRENTGATEWAY% | find "TTL="
	  if errorlevel 1 goto ChangeGateway
	  </P><P>:: When we arrive here the gateway was reachable. Wait for a minute
	  :: 192.168.254.254 should be unreachable
	  ping 192.168.254.254 -n 1 -w 60000 >NUL

	  goto CheckGateway

	  :ChangeGateway
	  if "%GATEWAY1%"=="%CURRENTGATEWAY%"	goto ChangeGateway2
	  set CURRENTGATEWAY=%GATEWAY1%
	  call ChangeGateway.cmd %CURRENTGATEWAY%
	  goto CheckGateway

	  :ChangeGateway2
	  set CURRENTGATEWAY=%GATEWAY2%
	  call ChangeGateway.cmd %CURRENTGATEWAY%
	  goto CheckGateway

When you use this code you'll have to retype the | between ping and find.

 

[Kidscorpion]

HI Mijzelf,

Thanks for your help.

I will try and revert to you.

Have a nice day.