<#
.Synopsis
   Script to Automated DHCP Migration
.DESCRIPTION
   Takes DHCP Configuration from Source server and converts to Destination (local server) configuration.
.EXAMPLE
  .\migrate-dhcp.ps1 -source sbs2011server
.EXAMPLE  
  .\migrate-dhcp.ps1 -source sbs2011server -detailed
#>
param(
    [Parameter(Mandatory=$True,Position=0)]
    [string]$source,
    [switch]$detailed
)
$destination = $env:Computername
$sourceIp = [System.Net.Dns]::GetHostAddresses($source)
$sourceIP = $sourceIP.IPAddressToString
$currentIP = get-netIPConfiguration
$destIntAlias = $currentIP.InterfaceAlias
$destIP = $currentIP.IPv4Address.IPAddress.ToString()
$destIPv6 = $currentIP.ipv6linklocaladdress.ipAddress
Write-Output "DHCP Migration "
Write-Output "Source           : $source"
Write-Output "Source IP        : $sourceIP"
Write-Output "Destination      : $destination"
Write-Output "Destination IP   : $destIP"
Write-Output "Destination IPv6 : $destIPv6"
Write-Output "Reading DHCP Configuration.. Please Wait"
$dhcpConfig = netsh dhcp server "\\$source" dump
if(($dhcpConfig) -like "Unable*")
{
    Write-Output "Error Collecting DHCP Configuration : $source"
    Write-Output "Check DHCP Service is Running on Source Server!"
}
else
{
    Write-Output "Processing DHCP Configuration.. Please Wait"
    foreach ($line in $dhcpConfig)
    {
        
        if(($line) -like "dhcp*")
        {
            try
            {
                if($line.Contains($source))
                {
                   $line = $line.Replace("$source","$destination")    
                }
                if($line.Contains($sourceIp))
                {
                    if($line.Contains("Add iprange") -or ($line.Contains("optionvalue 3") -or ($line.Contains("add excluderange"))))
                    {
                        # Skip Line Changes
                    }
                    else
                    {
                        $line = $line.Replace("$sourceIP","$destIP")    
                    }
                }
                if($line.Contains("23 IPV6ADDRESS"))
                {
                   $line = $line.Split("""")
                   $sourcev6 = $line[1]
                   $line = $line.Replace("$sourcev6","$destIPv6")
                   $line = $line.Replace("%3","")
                }
                if($line.Contains("Local Area Connection"))
                {
                    $line = $line.Replace("Local Area Connection","$destIntAlias")
                }
                $command = "netsh $line"
                if($detailed)
                {
                    Write-Output $command
                }
                cmd /c $command | Out-Null
            }
            catch
            {
                $errorMessage = $_.exception.message
            }
        }
    }
    Add-DhcpServerInDC -DnsName $destination -IPAddress $destIP
    Set-DhcpServerv4DnsSetting -ComputerName $destination -DynamicUpdates Always -DeleteDnsRROnLeaseExpiry $true
    $username = "$env:UserDomain\$env:userName"
    $pwd = Read-Host -AsSecureString -Prompt "Enter Password for $username for DHCP/DNS Update"
    $cred = New-Object System.Management.Automation.PSCredential($username,$pwd)
    Set-DHCPServerDNSCredential $cred
    Set-DHCPServerSetting -ConflictDetectionAttempts 2
    Write-Output "Disable DHCP Service on : $source"
    Write-Output "Stop DHCP Service on    : $source"
    Get-Service -ComputerName $source -ServiceName dhcpserver | Set-Service -StartupType Disabled
    Get-Service -ComputerName $source -ServiceName dhcpserver | Stop-Service -Force
    Write-Output "DHCP Configuration Complete"
}