Script to fix SCCM Multicast Issue (KB2419357)

I've been working with getting multicast distribution points working with SCCM 2007 R2 recently and one of the challenges is that there is a bug where some WDS settings are not correctly updated on the target server. Microsoft Knowledge Base article KB2419357 documents the issue.

I wrote the following script to update the required settings instead of having to do this manually. The script also makes a change to the ‘ApBlockSize’ setting for WDS, in our environment, where the server is on a 1GB switch port and the clients are on a remote segment on a 100MB switch port, this setting significantly reduced packet fragmentation and increased the speed of the multicast download. I have it in a package and advertise the script to servers hosting multicast enabled distribution points.

# ------------------------------------------------------------------
# Purpose: Applies some registry settings, mostly related to the 
# problem identified in KB2419357. It also makes a change to WDS 
# network settings to improvea packet fragmentation issue identified
# during testing of multicast with SCCM
# 
# Usage : powershell.exe -file .\wdsconfig.ps1
# 
# Version 1.0
# 
# Maintenance History
# ------------------------------------------------------------------
# Version - Date - Change - Author
# ------------------------------------------------------------------
# 1.0 21/11/12 Script Created JustAnotherTechnicalBlog
# 
# ------------------------------------------------------------------

# Set variables
$WDSRegRoot = "HKLM:System\CurrentControlSet\Services\WDSServer"
$WDSService = "Windows Deployment Services Server"


# Write the required SCCM options to the WDS configuration settings
# to the registry
If (Test-Path $WDSRegRoot\Parameters)
{
 Set-ItemProperty -Path $WDSRegRoot\Parameters -Name McStartAddr `
                                               -Value "239.10.10.10"
 Set-ItemProperty -Path $WDSRegRoot\Parameters -Name McEndAddr `
                                               -Value "239.10.10.10"
 Set-ItemProperty -Path $WDSRegRoot\Parameters -Name UdpStartPort `
                                               -Value "63000"
 Set-ItemProperty -Path $WDSRegRoot\Parameters -Name UdpEndPort `
                                               -Value "64000"
}


# Tune the network settings for the WDS server to reduce likelihood
# of packet fragmentation
If (Test-Path $WDSRegRoot\Providers\WDSMC\Protocol)
{
 Set-ItemProperty -Path $WDSRegRoot\Providers\WDSMC\Protocol `
                                               -Name ApBlockSize `
                                               -Value 1385
}


# Restart the Windows Deployment Services Server service
if (Get-Service $WDSService -ea SilentlyContinue)
{
 Restart-Service -displayname $WDSService
}