The following script is an amalgamation of several tools I’ve built up over the last couple of years to work with multiple DHCP scopes on servers. It has 6 basic modes of operation, as detailed below, which allow you to list all scopes on a server, enable all scopes on a server, disable all scopes on a server, change the lease time for all scopes on a server, change the offer delay for all scopes on a server or add reservations to one or more servers. You can use help .\DHCP-Tool.ps1 to get more information on the various switches, though it’s worth pointing out that leasetimes are in seconds while delaytimes are in milliseconds.
Hopefully the new Server 2012 powershell modules for DHCP solve a lot of these problems, but I haven’t had a chance to dig into them yet.
.\DHCP-Tool.ps1 -Server <String> [-show]
.\DHCP-Tool.ps1 -Server <String> [-enable]
.\DHCP-Tool.ps1 -Server <String> [-disable]
.\DHCP-Tool.ps1 -Server <String> [-lease] -leasetime <String>
.\DHCP-Tool.ps1 -Server <String> [-delay] -delaytime <Int32>
.\DHCP-Tool.ps1 -Server <String> [-reserve] -ipscope <String> -ipaddr <String> -mac <String> [-altservers <String>] [-name <String>]
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<#
.SYNOPSIS
DHCP Multitool
.DESCRIPTION
Provides a variety of functions for making changes to multiple DHCP scopes and/or multiple DHCP servers
.PARAMETER Server
The hostname or IP address of the DHCP server to work with
.PARAMETER Show
Action: List current scope configuration
.PARAMETER Enable
Action: Enable all scopes on server
.PARAMETER Disable
Action: Disable all scopes on server
.PARAMETER Lease
Action: Alters lease time on all scopes on server
.PARAMETER LeaseTime
DHCP Lease time in seconds
.PARAMETER Delay
Action: Alters offer delay on all scopes on server
.PARAMETER DelayTime
Offer Delay time in miliseconds
.PARAMETER Reserve
Action: Add reservation to server
.PARAMETER AltServer
Additional servers to create reservation on
.PARAMETER IPScope
Name of scope to work with
.PARAMETER IPAddr
IP Address to reserve
.PARAMETER MAC
MAC Address to associated reservation with
.PARAMETER Name
Comment to add to reservation
.EXAMPLE
C:\>dhcp-tool.ps1 -server 127.0.0.1 -enable
Enables all scopes on server 127.0.0.1
.EXAMPLE
C:\>dhcp-tool.ps1 -server 127.0.0.1 -delay -delaytime 1000
Sets an offer delay of 1000ms on all scopes on server 127.0.0.1
.NOTES
Author: Adam Beardwood
Date: October 12, 2012
v1.0: Initial Release
v1.1: Added Better Error Handling and Command Feedback
#>
[CmdletBinding(DefaultParametersetName="showDHCP")]
Param(
[Parameter(Mandatory=$true,ValueFromPipeline=$true)][String]$Server,
[Parameter(ParameterSetName='showDHCP')][switch]$show,
[Parameter(ParameterSetName='enableDHCP')][switch]$enable,
[Parameter(ParameterSetName='disableDHCP')][switch]$disable,
[Parameter(ParameterSetName='leaseDHCP')][switch]$lease,
[Parameter(ParameterSetName='leaseDHCP',Mandatory=$true,ValueFromPipeline=$true)][string]$leasetime,
[Parameter(ParameterSetName='delayDHCP')][switch]$delay,
[Parameter(ParameterSetName='delayDHCP',Mandatory=$true,ValueFromPipeline=$true)][ValidateRange(0,1000)][int]$delaytime,
[Parameter(ParameterSetName='reserveDHCP')][switch]$reserve,
[Parameter(ParameterSetName='reserveDHCP',Mandatory=$true)][string]$ipscope,
[Parameter(ParameterSetName='reserveDHCP',Mandatory=$true)][string]$ipaddr,
[Parameter(ParameterSetName='reserveDHCP',Mandatory=$true)][string]$mac,
[Parameter(ParameterSetName='reserveDHCP',Mandatory=$false)][string]$altservers = $null,
[Parameter(ParameterSetName='reserveDHCP',Mandatory=$false)][string]$name
)
function getDHCPScope($servername, $type) {
$ips = @()
$scopes = netsh dhcp server $servername show scope
if($type -eq "show"){
foreach($scope in $scopes){
write-host $scope -foregroundcolor green
}
}else{
$regex = [regex]"\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}"
foreach($scope in $scopes){
$addr = $scope | foreach {$regex.Matches($_) | foreach {$_.Captures[0].Value}}
if($addr -ne $null){
$ips += $addr[0]
}
}
return $ips
}
}
function enableDHCPScope($servername, $ip){
netsh dhcp server $servername scope $ip set state 1 | out-null
}
function disableDHCPScope($servername, $ip){
netsh dhcp server $servername scope $ip set state 0 | out-null
}
function leaseDHCPScope($servername, $ip, $leasetime){
netsh dhcp server $servername scope $ip set optionvalue 51 DWORD $leasetime | out-null
$leaseinfo = netsh dhcp server $servername scope $ip show optionvalue
foreach($info in $leaseinfo){if($info -match "OptionId : 51"){write-host "Scope $ip lease length: $($($leaseinfo[$([array]::IndexOf($leaseinfo, $info))+4]).split('=')[1]) seconds" -foregroundcolor green}}
}
function delayDHCPScope($servername, $ip, $leasetime){
netsh dhcp server $server scope $ip set delayoffer $delaytime | out-null
$delayinfo = netsh dhcp server $servername scope $ip show delayoffer
foreach($info in $delayinfo){if($info -match "DelayOffer"){write-host $info -foregroundcolor green}}
}
function reserveDHCPScope($servername, $altservers, $ipscope, $ipaddr, $mac, $name){
$servers = @($servername)
foreach($alt in $altservers){
if(($alt -ne "") -and ($alt -ne $null)){$servers += "\\$alt"}
}
write-host "Servers: $servers"
foreach($server in $servers){
$result = netsh dhcp server $server scope $ipscope
if($result -match "The command needs a valid Scope IP Address"){
write-host "Scope Does Not Exist!"
exit 1
}
$result = netsh dhcp server $server scope $ipscope show clients
if($result -match $ipaddr){
write-host "IP Address Already Reserved!"
exit 1
}
$regex = [regex]"([0-9A-Fa-f]{2}[:-]*){5}([0-9A-Fa-f]{2})"
$result = $mac | foreach {$regex.Matches($_) | foreach {$_.Captures[0].Value}}
if($result -eq $null){
write-host "Invalid MAC Address!"
exit 1
}
netsh dhcp server $server scope $ipscope add reservedip $ipaddr $mac $name
}
}
if($(Get-Service -ComputerName $server -Name DHCPServer -ErrorAction SilentlyContinue) -eq $null){
write-host "The specified server does not appear to be running DHCP"
exit 1
}
$servername = "\\$server"
switch ($PsCmdlet.ParameterSetName){
"showDHCP"{getDHCPScope $servername "show" }
"enableDHCP"{foreach($ip in $(getDHCPScope $servername)){enableDHCPScope $servername $ip};getDHCPScope $servername "show"}
"disableDHCP"{foreach($ip in $(getDHCPScope $servername)){disableDHCPScope $servername $ip};getDHCPScope $servername "show"}
"leaseDHCP"{foreach($ip in $(getDHCPScope $servername)){leaseDHCPScope $servername $ip $leasetime}}
"delayDHCP"{foreach($ip in $(getDHCPScope $servername)){delayDHCPScope $servername $ip $delaytime}}
"reserveDHCP"{reserveDHCPScope $servername $altservers $ipscope $ipaddr $mac $name}
}