#Requires -Version 5.1
<#
    JbTecWiz Support Centre -- generated fix script

    Fault : DNS event 4013 -- waiting for Active Directory to signal it has completed initial synchronisation
    Fix   : Restore replication with the partner
    Source: https://jbtecwiz.com/support/srv-dns-4013

    Run as     : Elevated PowerShell
    Expect     : 30-60 minutes
    Risk       : high
    Reversible : NO -- read the undo note below before running

    WHEN THIS IS THE RIGHT FIX
    There is more than one DC. Do NOT apply the single-DC registry change
    here -- find out why the partner is unreachable instead.

    HOW TO UNDO IT
    If the DC is past tombstone lifetime, forcibly demote it and clean up
    its metadata, then promote it fresh.

    This script walks the fix one step at a time and asks before each
    one. Steps with no command are things you do yourself -- it prints
    those and waits. Run with -DryRun to print without executing.

    --------------------------------------------------------------------
    NO WARRANTY - USE AT YOUR OWN RISK

    This script is provided by JbTecWiz as-is and with no warranty of any
    kind, express or implied. You run it entirely at your own risk.

    JbTecWiz accepts no liability for any loss or damage arising from its
    use, including but not limited to data loss, downtime, or configuration
    changes that turn out to be wrong for your system.

    You are responsible for reading this script before running it, for
    satisfying yourself that it suits the machine in front of you, and for
    having a working backup first. Some steps cannot be undone.
    --------------------------------------------------------------------
#>

[CmdletBinding()]
param(
    # Print every step and command without running anything.
    [switch]$DryRun,
    # Do not ask before each step. Read the script first if you use this.
    [switch]$Unattended
)

$ErrorActionPreference = 'Stop'
$script:Failed = 0

function Write-Rule { param([string]$Text)
    Write-Host ''
    Write-Host ('-' * 70) -ForegroundColor DarkGray
    if ($Text) { Write-Host $Text -ForegroundColor Cyan }
}

function Show-Prose { param([string]$Text, [string]$Colour = "Gray")
    if (-not $Text) { return }
    $words = $Text -split "\s+"; $line = "  "
    foreach ($w in $words) {
        if (($line.Length + $w.Length) -gt 74) { Write-Host $line -ForegroundColor $Colour; $line = "  " }
        $line += "$w "
    }
    if ($line.Trim()) { Write-Host $line -ForegroundColor $Colour }
}

function Invoke-Step {
    param(
        [int]$Number, [string]$Do, [string]$Why,
        [scriptblock]$Command, [switch]$Manual, [string]$Shell = "powershell"
    )
    Write-Rule "  Step $Number of 4"
    Show-Prose $Do "White"
    if ($Why) { Write-Host ""; Show-Prose $Why "DarkGray" }

    if ($Manual) {
        Write-Host ''
        Write-Host '  -> Do this yourself, then press Enter to carry on.' -ForegroundColor Yellow
        if (-not $Unattended -and -not $DryRun) { [void](Read-Host) }
        return
    }

    Write-Host ''
    foreach ($l in ($Command.ToString().Trim() -split "`n")) {
        Write-Host ("    " + $l.Trim()) -ForegroundColor Green
    }
    Write-Host ''

    if ($DryRun) { Write-Host "  (dry run -- not executed)" -ForegroundColor DarkGray; return }
    if (-not $Unattended) {
        $a = Read-Host "  Run this step? [Y]es / [S]kip / [Q]uit"
        if ($a -match "^[Qq]") { Write-Host "  Stopped at your request."; exit 0 }
        if ($a -match "^[Ss]") { Write-Host "  Skipped." -ForegroundColor DarkGray; return }
    }
    try { & $Command }
    catch {
        $script:Failed++
        Write-Host ("  Step $Number failed: " + $_.Exception.Message) -ForegroundColor Red
        Show-Prose "The rest of the fix may depend on this. Read the write-up before carrying on." "Red"
        if (-not $Unattended) {
            $c = Read-Host "  Carry on anyway? [y/N]"
            if ($c -notmatch "^[Yy]") { exit 1 }
        }
    }
}

Write-Rule
Write-Host '  DNS event 4013 -- waiting for Active Directory to signal it has completed initial synchronisation' -ForegroundColor White
Write-Host '  Restore replication with the partner' -ForegroundColor Cyan
Write-Host ''
Write-Host '  Risk: high   NOT REVERSIBLE   30-60 minutes' -ForegroundColor Yellow
Write-Host ''
Show-Prose 'Undo: If the DC is past tombstone lifetime, forcibly demote it and clean up its metadata, then promote it fresh.' 'Yellow'
Write-Host ''
Show-Prose 'No warranty. Use at your own risk - JbTecWiz accepts no liability. Read it before you run it, and have a backup.' 'DarkYellow'
Write-Rule

if (-not $Unattended -and -not $DryRun) {
    $go = Read-Host '  Ready? [y/N]'
    if ($go -notmatch "^[Yy]") { Write-Host "  Nothing was changed."; exit 0 }
}

Invoke-Step -Number 1 -Do 'Check how long this DC has been out of touch. If it exceeds the tombstone lifetime, it must be demoted and rebuilt rather than reconnected.' -Why 'Reintroducing a DC that has been offline longer than the tombstone lifetime resurrects deleted objects across the forest. That is far worse than the outage you are fixing.' -Command {
    repadmin /showrepl
    Get-ADObject -Identity ((Get-ADDomain).DistinguishedName) -Properties tombstoneLifetime
}

Invoke-Step -Number 2 -Do 'Confirm the partner is reachable on the network and by name.' -Command {
    Test-NetConnection DC02 -Port 389
    Resolve-DnsName DC02
}

Invoke-Step -Number 3 -Do 'Point this DC''s DNS client at a working partner rather than itself.' -Command {
    Set-DnsClientServerAddress -InterfaceAlias 'Ethernet' -ServerAddresses 10.0.0.11,127.0.0.1
}

Invoke-Step -Number 4 -Do 'Restart the DC, then force replication.' -Command {
    repadmin /syncall /AdeP
}

Write-Rule "  Confirm it worked"
Show-Prose 'repadmin reports successful replication and event 4013 does not recur on restart.' 'White'
Write-Host ''
if (-not $DryRun) {
    repadmin /replsummary
}

Write-Rule
if ($script:Failed -gt 0) {
    Write-Host ("  Finished with " + $script:Failed + " failed step(s).") -ForegroundColor Yellow
    Show-Prose 'Read the full write-up at https://jbtecwiz.com/support/srv-dns-4013' 'Yellow'
} else {
    Write-Host '  Finished.' -ForegroundColor Green
}
Write-Host ''
Show-Prose 'To undo: If the DC is past tombstone lifetime, forcibly demote it and clean up its metadata, then promote it fresh.' 'DarkGray'
Write-Rule