Create Validate-NetSettings.ps1

PowerShell/Validate-NetSettings.ps1

@@ -0,0 +1,34 @@
+#Test network settings for common errors.  Ensures IP Address, Gateway, and DNS Servers are all valid IP addresses and that the Subnet Mask is a valid mask.  Returns the Subnet Mask in CIDR notation if everything is successful.
+#Ensures tha the Gateway address is on the same subnet as the provided IP Address.
+#Usage: Validate-NetSettings -ipAddress <IP> -gateway <Gateway> -subnetMask <subnet mask in dotted notation> -DNSServers <Array of DNS Server IPs>
+param (
+	[Parameter(Mandatory=$true)]
+	[string]$ipaddress,
+
+	[Parameter(Mandatory=$true)]
+	[string]$gateway,
+
+	[Parameter(Mandatory=$true)]
+	[string]$subnetMask,
+
+	[Parameter(Mandatory=$true)]
+	[string[]]$DNSServers
+)
+
+try {
+	$ipSubnet = ([ipaddress](([ipaddress]$ipaddress).address -band ([ipaddress]$subnetMask).address)).ipaddresstostring
+	$gatewaySubnet = ([ipaddress](([ipaddress]$Gateway).address -band ([ipaddress]$subnetMask).address)).ipaddresstostring
+	if ($ipSubnet -ne $gatewaySubnet){
+		throw "IP Address $($ipAddress) with Subnet Mask $($subnetMask) cannot access Gateway $($gateway)"
+	}
+	$subnetMaskBinary = ($SubnetMask -split "\." | % {[convert]::tostring($_,2).padleft(8,"0")}) -join ""
+	if ($subnetMaskBinary -notmatch "(^1+)0+$" -or $subnetMaskBinary.length -ne 32){throw "Invalid subnet mask: $(subnetmask)"}
+	$subnetCIDR = $matches[1].length
+	$DNSServers | % {
+		[ipaddress]$_ | out-null
+	}
+	return $subnetCIDR
+}
+catch {
+	return $_.Exception.Message
+}