Powershell - 检查 IP，循环重试并发送电子邮件

问题描述

我一直在尝试编写脚本，以便 powershell 检查我们的外部 ip - 如果它没有改变 - 什么都不做，只记录它被检查过。

如果脚本认为它已更改，请重试，如果尝试 5 次后它已更改，则发送电子邮件。

我已经包括了我到达的地方，但我今天无法（疲倦或愚蠢）让它发挥作用，所以把它扔给蜂巢寻求帮助！

附件是我也得到的地方！干杯CM

 #find old ip
$oldip = gc .\ip.txt

#get current ip address
$currentip = (New-Object net.webclient).downloadstring("http://api.ipify.org")

#current date and time
$currentTime = Get-Date -format "dd-MMM-yyyy HH:mm:ss"

#script location
$scriptpath = $MyInvocation.MyCommand.DeFinition 
[string]$dir = Split-Path $scriptpath  
set-location $dir

#set the smtp server URL here
$smtpServer = "smtp.my.com"

#Set the Sender Name or Email here
$sender = "[e-mail]"

#Enter the email reciepients here - you can send to multiple using format: "[e-mail]","[e-mail]";
$users = "[e-mail]";

#Enter the subject title the reciepient see's here
$subject = "IP Has Changed" 

#Type out the email contents here
$body = "Dear Team Member,Your IP address at has just changed from:  $oldip

And is Now set too:  $currentip 

Regards." 


#*****************************************************************************************************************************************

do {
    $Result = ($oldip -ne $currentip)
    if ($Result.Status -eq "Success") {
        Write-Output "IP Address Unchanged - Monitoring Continues."
        Add-Content $PSScriptRoot\IP_Check_Log.txt "$currentTime - IP Unchanged. "
        Start-Sleep -s 2
        Exit 0
    }
    else {
       Write-Output "Ping Failed!"
       Add-Content $PSScriptRoot\IP_Check_Log.txt "$currentTime - IP Check Failed - retrying"
       $Failures += 5
    }
} until ($Failures -ge $FailureThreshold)
Write-Output "IP Address Changed!"
Add-Content $PSScriptRoot\IP_Check_Log.txt "$currentTime - IP AddeRSS Changed. "
Add-Content $PSScriptRoot\IP_Check_Log.txt "*****************************************************************************"

#be sure to alter the SMTP server port here if needed.
    $smtp = New-Object Net.Mail.SmtpClient($smtpServer,587) 
    $smtp.EnableSsl = $true 

#Enter the sending email address and password here
    $smtp.Credentials = New-Object System.Net.NetworkCredential("[e-mail]","password"); 
    $smtp.Send($sender,$user,$subject,$body)

解决方法

在这里使用 do{..} until(..) 循环可能比使用 for 更容易，我会在此使用 try{..} catch{..}。

在循环内部获取新的 ip 地址，不要获取一次并继续遍历该实例。

可能是这样的（省略了电子邮件内容）

$logFile = Join-Path -Path $PSScriptRoot -ChildPath 'IP_Check_Log.txt'
$FailureThreshold = 5

# find old ip
$oldip = [IPAddress](Get-Content .\ip.txt)

$ipchanged = $false
$currentip = $null
for ($i = 0; $i -lt $FailureThreshold; $i++) {
    try {
        # try to get the get current ip address
        $currentip = [IPAddress](New-Object net.webclient).DownloadString("http://api.ipify.org")
        if ($currentip -eq $oldip) {
            Write-Output "IP Address Unchanged - Monitoring Continues."
            Add-Content -Path $logFile -Value "$currentTime - IP Unchanged. "
            exit 0
        }
        else {
            $ipchanged = $true
        }
    }
    catch {
        $currentip = $null
        $ipchanged = $false
        Write-Output "Ping Failed!"
        Add-Content -Path $logFile -Value "$currentTime - IP Check Failed - Retrying"
    }
    Start-Sleep -Seconds 2
}

# test if the above returned a $currentip not $null and if boolean $ipchanged is $true
if (($currentip) -and $ipchanged) {
    Write-Output "IP Address Changed!"
    Add-Content  -Path $logFile -Value "$currentTime - IP Address Changed. "
    Add-Content  -Path $logFile -Value "*****************************************************************************"

    # refresh the .\ip.txt file to store the new ip?
    Set-Content -Path .\ip.txt -Value $currentip.IPAddressToString

    # send the email
}

^{我对 [IPAddress] 使用强制转换，因为如果 .DownloadString() 失败或它返回一些不是 IP 地址的东西，您将进入 catch 块，以便您可以处理错误上>}