DHCP backups: what Windows does for you, and what it doesn't

If a DHCP server dies, every new device on the network stops getting an address. Knowing exactly how DHCP is backed up saves a lot of panic.

Three different "backups"

The trap is thinking an export is incremental. It isn't. It only contains what DHCP looked like at the moment you ran it. Add a reservation afterwards and it's not in the file.

A nightly export that keeps a week

The export file is tiny, so there's no reason not to take one every night. This script saves a dated copy and deletes anything older than seven days. I save it as C:\Scripts\DhcpBackup.ps1.

# DHCP nightly export - keeps the last 7 days
$folder = "C:\Backup\DHCP"
$file   = "$folder\dhcp-$(Get-Date -Format yyyy-MM-dd).xml"

New-Item -ItemType Directory -Path $folder -Force | Out-Null
Export-DhcpServer -File $file -Leases -Force

Get-ChildItem $folder -Filter "dhcp-*.xml" |
    Where-Object { $_.LastWriteTime -lt (Get-Date).AddDays(-7) } |
    Remove-Item -Force

Then schedule it to run at 2am as SYSTEM:

$action  = New-ScheduledTaskAction -Execute "powershell.exe" `
  -Argument '-NoProfile -ExecutionPolicy Bypass -File "C:\Scripts\DhcpBackup.ps1"'
$trigger = New-ScheduledTaskTrigger -Daily -At 2am
Register-ScheduledTask -TaskName "DHCP Nightly Export" `
  -Action $action -Trigger $trigger -User "SYSTEM" -RunLevel Highest

Test it straight away rather than waiting for 2am:

Start-ScheduledTask -TaskName "DHCP Nightly Export"
Get-ChildItem C:\Backup\DHCP

In Task Scheduler, a Last Run Result of 0x0 means success.

Restoring

Import-DhcpServer -File C:\Backup\DHCP\dhcp-2026-10-18.xml `
  -BackupPath C:\Backup\DhcpImportBackup -Leases

Then authorise the server in Active Directory and check the scopes.