Automating Network Configuration Backup and DHCP to Static IP Conversion in PowerShell

Network configuration is crucial for system administrators managing multiple servers and devices. Automating the backup and conversion of network settings from DHCP to a static IP can save time and reduce errors. The PowerShell script below accomplishes this by backing up current network configurations and then converting DHCP-assigned IP addresses to static ones.

Here’s a detailed breakdown of how this script works and how you can utilize it effectively.

Script Overview

The PowerShell script ensures it runs with administrative privileges, checks if the backup directory exists and has the necessary write permissions, backs up current network configurations, and then converts DHCP-configured network adapters to static IP configurations.

Script Breakdown

1. Ensure Administrative Privileges

The script starts by checking if it is running with administrative privileges. Many network configuration commands require elevated permissions.

if (-not ([System.Security.Principal.WindowsPrincipal][System.Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([System.Security.Principal.WindowsBuiltInRole]::Administrator)) {
    Write-Host "Please run this script with administrative privileges."
    exit
}

2. Define Backup File Path

The script defines a backup directory and file where the network configuration will be saved.

$backupDirectory = "C:\temp"
$backupFile = Join-Path -Path $backupDirectory -ChildPath "network_config_backup.xml"

3. Ensure Backup Directory Exists

It ensures the backup directory exists or creates it if it doesn’t.

if (-not (Test-Path $backupDirectory)) {
    try {
        New-Item -Path $backupDirectory -ItemType Directory -Force -ErrorAction Stop
        Write-Host "Backup directory created: $backupDirectory"
    } catch {
        Write-Host "Failed to create backup directory: $backupDirectory. $_"
        exit
    }
}

4. Check Write Permissions

Before proceeding, the script checks for write permissions to the backup directory by attempting to create and delete a test file.

try {
    $testFile = [System.IO.Path]::Combine($backupDirectory, [System.IO.Path]::GetRandomFileName())
    New-Item -Path $testFile -ItemType File -Force -ErrorAction Stop
    Remove-Item -Path $testFile -Force
} catch {
    Write-Host "No write permissions to backup directory: $backupDirectory. $_"
    exit
}

5. Backup Current Configuration

It defines a function to backup current network configurations using Get-NetIPConfiguration and Export-Clixml.

function Backup-Configuration {
    param (
        [string]$FilePath
    )
    Get-NetIPConfiguration | Export-Clixml -Path $FilePath
}

6. Identify Connected Network Adapters

The script identifies network adapters that are currently connected.

$adapters = Get-NetAdapter | Where-Object { $_.Status -eq "Up" }

if (-not $adapters) {
    Write-Host "No active network adapters found."
    exit
}

7. Backup Configuration

The network configuration is backed up to the specified file.

Backup-Configuration -FilePath $backupFile
Write-Host "Network configuration backed up to $backupFile."

8. Convert DHCP to Static IP

For each adapter, the script checks if DHCP is enabled. If so, it retrieves the current DHCP settings, then converts these to static IP settings using New-NetIPAddress, Set-NetIPAddress, Set-NetRoute, and Set-DnsClientServerAddress.

foreach ($adapter in $adapters) {
    Write-Host "`nChecking adapter: $($adapter.Name)"
    
    $dhcpConfig = Get-NetIPConfiguration -InterfaceIndex $adapter.IfIndex
    
    if (-not $dhcpConfig.IPv4Address) {
        Write-Host "No IPv4 address found on adapter: $($adapter.Name)"
        continue
    }

    $dhcpEnabled = $dhcpConfig.IPv4Address | ForEach-Object { $_.PrefixOrigin -eq "Dhcp" }

    if ($dhcpEnabled -contains $true) {
        $adapterFound = $true
        
        $currentIPAddress = $dhcpConfig.IPv4Address.IPAddress
        $currentSubnetMask = $dhcpConfig.IPv4Address.PrefixLength
        $currentGateway = $dhcpConfig.IPv4DefaultGateway.NextHop
        $currentDNSServers = $dhcpConfig.DNSServer.ServerAddresses

        Write-Host "`nCurrent DHCP Configuration for adapter: $($adapter.Name)"
        Write-Host "IP Address: $currentIPAddress"
        Write-Host "Subnet Mask: $currentSubnetMask"
        Write-Host "Gateway: $currentGateway"
        Write-Host "DNS Servers: $($currentDNSServers -join ', ')"

        try {
            $existingIP = Get-NetIPAddress -InterfaceIndex $adapter.IfIndex -AddressFamily IPv4 -ErrorAction SilentlyContinue

            if ($existingIP) {
                Set-NetIPAddress -InterfaceIndex $adapter.IfIndex `
                                 -IPAddress $currentIPAddress `
                                 -PrefixLength $currentSubnetMask `
                                 -AddressFamily IPv4 `
                                 -Confirm:$false
            } else {
                New-NetIPAddress -InterfaceIndex $adapter.IfIndex `
                                 -IPAddress $currentIPAddress `
                                 -PrefixLength $currentSubnetMask `
                                 -AddressFamily IPv4 `
                                 -Confirm:$false
            }

            if ($currentGateway) {
                $existingGateway = Get-NetRoute -InterfaceIndex $adapter.IfIndex -NextHop $currentGateway -ErrorAction SilentlyContinue

                if ($existingGateway) {
                    Set-NetRoute -InterfaceIndex $adapter.IfIndex `
                                 -NextHop $currentGateway `
                                 -DestinationPrefix "0.0.0.0/0" `
                                 -RouteMetric 1 `
                                 -Confirm:$false
                } else {
                    New-NetRoute -InterfaceIndex $adapter.IfIndex `
                                 -NextHop $currentGateway `
                                 -DestinationPrefix "0.0.0.0/0" `
                                 -RouteMetric 1 `
                                 -Confirm:$false
                }
            }

            Set-DnsClientServerAddress -InterfaceIndex $adapter.IfIndex `
                                       -ServerAddresses $currentDNSServers `
                                       -Confirm:$false

            $newConfig = Get-NetIPConfiguration -InterfaceIndex $adapter.IfIndex

            Write-Host "`nConverted to Static IP Configuration for adapter: $($adapter.Name)"
            Write-Host "IP Address: $($newConfig.IPv4Address.IPAddress)"
            Write-Host "Subnet Mask: $($newConfig.IPv4Address.PrefixLength)"
            Write-Host "Gateway: $($newConfig.IPv4DefaultGateway.NextHop)"
            Write-Host "DNS Servers: $($newConfig.DNSServer.ServerAddresses -join ', ')"
        } catch {
            Write-Host "Error converting DHCP to Static on adapter: $($adapter.Name). $_"
        }
    } else {
        Write-Host "DHCP is not enabled on adapter: $($adapter.Name)"
    }
}

if (-not $adapterFound) {
    Write-Host "`nNo active adapters with DHCP enabled were found."
}

Using the Script

Preparation:

1. Ensure you have administrative privileges.
Modify $backupDirectory and $backupFile paths as needed.
Execution:

2. Run the script in a PowerShell session with elevated privileges.
Observe the output to confirm successful backup and conversion.
Verification:

3. Check the backup file for accuracy.
Verify the static IP configuration using Get-NetIPConfiguration or similar commands.

Complete Script Convert DHCP IP to Static with Directory Creation

# Ensure script runs with administrative privileges
if (-not ([System.Security.Principal.WindowsPrincipal][System.Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([System.Security.Principal.WindowsBuiltInRole]::Administrator)) {
    Write-Host "Please run this script with administrative privileges."
    exit
}

# Define backup file path
$backupDirectory = "C:\temp"
$backupFile = Join-Path -Path $backupDirectory -ChildPath "network_config_backup.xml"

# Ensure the backup directory exists
if (-not (Test-Path $backupDirectory)) {
    try {
        New-Item -Path $backupDirectory -ItemType Directory -Force -ErrorAction Stop
        Write-Host "Backup directory created: $backupDirectory"
    } catch {
        Write-Host "Failed to create backup directory: $backupDirectory. $_"
        exit
    }
}

# Check for write permissions to the backup directory
try {
    $testFile = [System.IO.Path]::Combine($backupDirectory, [System.IO.Path]::GetRandomFileName())
    New-Item -Path $testFile -ItemType File -Force -ErrorAction Stop
    Remove-Item -Path $testFile -Force
} catch {
    Write-Host "No write permissions to backup directory: $backupDirectory. $_"
    exit
}

# Backup existing configuration to a file
function Backup-Configuration {
    param (
        [string]$FilePath
    )
    Get-NetIPConfiguration | Export-Clixml -Path $FilePath
}

# Get all network adapters that are currently connected
$adapters = Get-NetAdapter | Where-Object { $_.Status -eq "Up" }

if (-not $adapters) {
    Write-Host "No active network adapters found."
    exit
}

$adapterFound = $false

# Backup existing configuration
Backup-Configuration -FilePath $backupFile
Write-Host "Network configuration backed up to $backupFile."

foreach ($adapter in $adapters) {
    Write-Host "`nChecking adapter: $($adapter.Name)"
    
    # Retrieve the current IP configuration
    $dhcpConfig = Get-NetIPConfiguration -InterfaceIndex $adapter.IfIndex
    
    if (-not $dhcpConfig.IPv4Address) {
        Write-Host "No IPv4 address found on adapter: $($adapter.Name)"
        continue
    }

    $dhcpEnabled = $dhcpConfig.IPv4Address | ForEach-Object { $_.PrefixOrigin -eq "Dhcp" }

    if ($dhcpEnabled -contains $true) {
        $adapterFound = $true
        
        # Save current IP settings
        $currentIPAddress = $dhcpConfig.IPv4Address.IPAddress
        $currentSubnetMask = $dhcpConfig.IPv4Address.PrefixLength
        $currentGateway = $dhcpConfig.IPv4DefaultGateway.NextHop
        $currentDNSServers = $dhcpConfig.DNSServer.ServerAddresses

        Write-Host "`nCurrent DHCP Configuration for adapter: $($adapter.Name)"
        Write-Host "IP Address: $currentIPAddress"
        Write-Host "Subnet Mask: $currentSubnetMask"
        Write-Host "Gateway: $currentGateway"
        Write-Host "DNS Servers: $($currentDNSServers -join ', ')"

        # Convert DHCP to Static IP
        try {
            # Check if the IP address already exists
            $existingIP = Get-NetIPAddress -InterfaceIndex $adapter.IfIndex -AddressFamily IPv4 -ErrorAction SilentlyContinue

            if ($existingIP) {
                # If the IP exists, modify it
                Set-NetIPAddress -InterfaceIndex $adapter.IfIndex `
                                 -IPAddress $currentIPAddress `
                                 -PrefixLength $currentSubnetMask `
                                 -AddressFamily IPv4 `
                                 -Confirm:$false
            } else {
                # Otherwise, create a new static IP
                New-NetIPAddress -InterfaceIndex $adapter.IfIndex `
                                 -IPAddress $currentIPAddress `
                                 -PrefixLength $currentSubnetMask `
                                 -AddressFamily IPv4 `
                                 -Confirm:$false
            }

            # Set default gateway using Set-NetRoute
            if ($currentGateway) {
                $existingGateway = Get-NetRoute -InterfaceIndex $adapter.IfIndex -NextHop $currentGateway -ErrorAction SilentlyContinue

                if ($existingGateway) {
                    # If the gateway exists, modify it
                    Set-NetRoute -InterfaceIndex $adapter.IfIndex `
                                 -NextHop $currentGateway `
                                 -DestinationPrefix "0.0.0.0/0" `
                                 -RouteMetric 1 `
                                 -Confirm:$false
                } else {
                    # Otherwise, add a new default gateway route
                    New-NetRoute -InterfaceIndex $adapter.IfIndex `
                                 -NextHop $currentGateway `
                                 -DestinationPrefix "0.0.0.0/0" `
                                 -RouteMetric 1 `
                                 -Confirm:$false
                }
            }

            # Set DNS servers
            Set-DnsClientServerAddress -InterfaceIndex $adapter.IfIndex `
                                       -ServerAddresses $currentDNSServers `
                                       -Confirm:$false

            # Retrieve new configuration to confirm the change
            $newConfig = Get-NetIPConfiguration -InterfaceIndex $adapter.IfIndex

            Write-Host "`nConverted to Static IP Configuration for adapter: $($adapter.Name)"
            Write-Host "IP Address: $($newConfig.IPv4Address.IPAddress)"
            Write-Host "Subnet Mask: $($newConfig.IPv4Address.PrefixLength)"
            Write-Host "Gateway: $($newConfig.IPv4DefaultGateway.NextHop)"
            Write-Host "DNS Servers: $($newConfig.DNSServer.ServerAddresses -join ', ')"
        } catch {
            Write-Host "Error converting DHCP to Static on adapter: $($adapter.Name). $_"
        }
    } else {
        Write-Host "DHCP is not enabled on adapter: $($adapter.Name)"
    }
}

if (-not $adapterFound) {
    Write-Host "`nNo active adapters with DHCP enabled were found."
}

Conclusion
Automating the backup and configuration of network settings using PowerShell can streamline network management tasks. This script offers a reliable way to ensure network configurations are saved and easily convert DHCP settings to static IP addresses, simplifying network administration. Adapt and extend this script as needed to fit your specific network environment.