Add DNS test script

Author: benpiper

route53/dnstest.ps1

@@ -0,0 +1,59 @@
+param (
+    [Parameter(Mandatory)] [string]$hostname,
+    [Parameter(Mandatory)] [string]$nameserver,
+    [Parameter(Mandatory)] [int]$iterations,
+    [Parameter(Mandatory)] [int]$sleeptime
+)
+
+function Run-NSLookup {
+    param (
+        [Parameter(Mandatory)] [string]$hostname,
+        [Parameter(Mandatory)] [string]$nameserver
+    )
+
+    $ns = (nslookup.exe $hostname $nameserver)[-2] 2>$null
+    $lookup = [PSCustomObject]@{
+        Address = ($ns -split ':')[1].Trim()
+    }
+    return $lookup.Address
+}
+
+function Iterate-NSLookup {
+    param (
+        [Parameter(Mandatory)] [string]$hostname,
+        [Parameter(Mandatory)] [string]$nameserver,
+        [Parameter(Mandatory)] [int]$iterations,
+        [Parameter(Mandatory)] [int]$sleeptime
+    )
+
+    $responses = @{}
+    write-host "Working..."
+
+    for ($i=0; $i -lt $iterations; $i++) {
+        #Query DNS
+        try {$ip = Run-NSLookup -hostname $hostname -nameserver $nameserver }
+        catch { "Name resolution failed. Please check the hostname."; exit}
+
+        #if address is in hashtable, increment counter
+        if ($responses[$ip] -ge 1) { $responses[$ip]++ }
+        else {
+            $responses.Add($ip,1)
+            Write-Host Resolved unique IP: $ip
+        }
+        Start-Sleep -seconds $sleeptime
+    }
+
+    $recordlist = @()
+    $responses.keys | ForEach-Object  {
+        $recordlist += New-Object PSObject -Property @{
+            'IP'=$_;
+            'Count'=$responses[$_];
+            'Percent'="{0:p}" -f ($responses[$_]/$iterations)
+        }
+    }
+    return $recordlist
+}
+
+$records = Iterate-NSLookup -hostname $hostname -nameserver $nameserver -iterations $iterations -sleeptime $sleeptime
+$records | Format-Table -Property ip,count,percent
+Write-Host $records.count "unique responses" for $hostname