有没有办法在互联网丢失时禁用和启用网络连接

Question

this is my first post so hopefully I am doing it right.

I am looking for a way to automate the process of disabling my Ethernet network connection and then reenable it.

I am on a camp internet connection (work away for weeks at a time) and the internet connection is fine besides it dropping out every half an hour or so and requiring me to refresh the connection. Usually I just disconnect the Ethernet plug for a second and plug it back in but I am wanting to automate the process so I can remote connect to the pc when I am away.

Any help on how to accomplish this would be appreciated.

Edit: I left a vital part out of my description. I am wanting the script to detect when the internet connection is lost and then refresh the connection. Once the connection is lost it never regains it until I refresh the connection.

Answer 1

You can handle this using Get-NetAdapter , Enable-NetAdapter and Disable-NetAdapter commands.

Answer 2

If you are using DHCP

Then Dollars to donuts you are just needing to renew your DHCP lease.

That is something you can do in CMD easily (I'm sure there is likely as easy a method in PS, but I don't know it offhand)

This will release the currently assigned DHCP Address wait a few seconds and then renew it.

IPConfig /Release & timeout 5 & IPConfig /Renew

At the CLI or in a batch script you could set up a do-while loop to loop until you return an expected up address if you wanted.

Example of a costume loop in cmd cli.

For /L %L (1,1,2147483648) DO (
  IPConfig /Release & timeout 3 & IPConfig /Renew &timeout 3 &(
    Ping -n 2 4.2.2.2 | find /I "Reply From" | find /I " 4.2.2.2"  &&(
      Exit /b 0
    )
  )
)

Disabling and enabling your NIC can be done through CMD or Powershell.

Here Powershell is easier.

Get only currently enabled adapters, use that to disable them wait a few seconds and enable them again

$NIC_Original_State = get-NetAdapter | ? {$_.Status -eq "Enabled"}
$NIC_Original_State | Disable-NetAdapter -name $_.name -confirm:$false
Sleep 5
$NIC_Original_State | Enable-NetAdapter -name $_.name -confirm:$false

Combine with checking the ping to the internet (as in cmd example) to generate a loop until we have a good connection.

$NIC_Original_State = get-NetAdapter | ? {$_.Status -eq "Enabled"}

DO {
  $NIC_Original_State | Disable-NetAdapter -name $_.name -confirm:$false
  Sleep 5
  $NIC_Original_State | Enable-NetAdapter -name $_.name -confirm:$false
  Sleep 5
} While ( ! $(test-connection -TargetName 4.2.2.2 -Quiet ) )

Now, PowerShell will need to be instantiated from a CMD prompt, I usually write a .cmd script wrapper for the .ps1 script to be called from in task scedualer or by hand.

Sometimes I will write a combo .cmd script with the ps code embedded and just create a hardline. To the original .cmd script as a. .ps1 to execute the ps code.

Although for something this simple it might be simplest to use PowerShell.exe to run the script as an in-line command.

But all roads lead to Rome, you do you on executing PowerShell, but in order to run it periodically, you will need to schedule the script to run, and by default there is no way to run ps scripts directly, so pick a method that you like that works for running the script and then use windows scheduler to schedule the task to run every x interval you like (say hourly)

Make surw you select a new task (not a basic task) and select run with highest priviledges" checkbox, and select the newest version of windows available in the compatibility list-box.

Make sure to provide a useename and password of an administrator, and select to save the password/run whether the user is logged on or not.

Set your triggers and put in the method you chose to execute the script and run some tests to make sure it works as expected.

Edit:

The original method is int he form DO { Action } WHILE ( Condition To Check Returns True ) Since the While is at the end it guarantees one iteration.

Since you don't want to disable and enable the NIC even once if the internet is pingable, you can use a WHILE ( Condition To Check Returns True ) { Action }

$NIC_Original_State = get-NetAdapter | ? {$_.Status -eq "Enabled"}

While ( ! $( test-connection -ComputerName 4.2.2.2 -Quiet ) ) {
  $NIC_Original_State | Disable-NetAdapter -name $_.name -confirm:$false
  Sleep 5
  $NIC_Original_State | Enable-NetAdapter -name $_.name -confirm:$false
  Sleep 5
}

You absolutely need to have a scheduled task to run this regularly.

Even if you want to only start it once and leave it in the background, and havit checking always (which we could do) you'll need to set up a scheduled task to kill it if still running and start it again at some interval as it's possible to have a process become unresponsive or be killed or have the computer restart etc and you forget to start the script etc.

This version will just loop every one minute to check, and only executes when the internet is not reachable.

while ($true) {
  $NIC_Original_State = get-NetAdapter | ? {$_.Status -eq "Enabled"}

  While ( ! $( test-connection -ComputerName 4.2.2.2 -Quiet ) ) {
    $NIC_Original_State | Disable-NetAdapter -name $_.name -confirm:$false
    Sleep 5
    $NIC_Original_State | Enable-NetAdapter -name $_.name -confirm:$false
    Sleep 5
  }
 sleep 60
}

Again, you ca just run this in powershell, sure, btu then if it gets stopped for any reason it won;t be started again.

Use task scheduler ad set up an action to run this o Startup and once an hour, killing any previously running copy of the script.

Usually for running a CMD script I just write a simple cmd script so if I want to edit any part of anything I only change the script never the task.

<# ## & REM Script Name:
@(
    SETLOCAL ENABLEDELAYEDEXPANSION
    ECHO OFF
    (
        NET SESSION 2>&1 >NUL
    ) || (
        powershell.exe -Command "Start-Process cmd \"/k %~dpnx0\" -Verb RunAs"
        pause
        GOTO :EOF
    )
    IF EXIST "%~dpn0.ps1" (
        DEL /Q /F %~dpn0.ps1"
    )
    MKLINK /H "%~dpn0.ps1" "%~f0"
)

Powershell.exe -ExecutionPolicy Bypass -File "%~dpn0.ps1"

(
  ENDLOCAL
  EXIT /B %_eLvl%
)

#>

## Script: 
## Powershell Portion Begins

while ($true) {
  $NIC_Original_State = get-NetAdapter | ? {$_.Status -eq "Enabled"}

  While ( ! $( test-connection -ComputerName 4.2.2.2 -Quiet ) ) {
    $NIC_Original_State | Disable-NetAdapter -name $_.name -confirm:$false
    Sleep 5
    $NIC_Original_State | Enable-NetAdapter -name $_.name -confirm:$false
    Sleep 5
  }
 sleep 60
}