Implement Microsoft Connected Cache with SCCM

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Check usage on the SCCM DP

A new directory is created on the server. It starts with the name “DOINC-” followed by a GUID. It takes some time until something happens here. Again, patience is required until the clients use the cache and it is filled.

Connected Cache Folder Properties on the SCCM DP
Connected Cache Folder Properties on the SCCM DP

Test you can test it with a corresponding Web request. Please replace with the name of the SCCM Distribution Point where you have set up Connected Cache.

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Invoke-WebRequest -URI "http://<SCCM-DP>/mscomtest/wuidt.gif" -Headers @{"Host"="b1.download.windowsupdate.com"}

This should return a status 200.

Test the cache accessibility with the PowerShell command Invoke-WebRequest
Test the cache accessibility with the PowerShell command Invoke-WebRequest

Overview in SCCM

In SCCM you can also display where the client received its data from. The display can be found under: “Monitoring” > “Overview” > “Distribution Status” > “Client Data Sources”.

Important, only the information for the SCCM clients is displayed here, not the other systems that still “co-use” the Connected Cache through DHCP, group policy or intune policy.

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Client Data Source view in the SCCM console
Client Data Source view in the SCCM console

Distributing the settings without SCCM

Since I also have cloud-only and stand-alone systems for testing, I would also like to use Delivery Optimization and the Connected Cache for this. Unfortunately, there are currently only available for the SCCM as a server, and not yet available as standalone for Windows Server 2019 or Ubuntu Server 18.04 as announced on the Ignite, fortunately, I just configured it in the SCCM. What a coincidence 🙂

Configuring Connected Cache with Group Policy

How do the systems without SCCM get their configuration? At the moment there is nothing definite about this, but the 20H1 might bring the announced support for configuration via DHCP option 235.

Another reference is a group policy that has been in place since 1909:

Group Policy from Windows 10 1909 Group Policy Templates
Computer generated alternative text:
[Reserved for future use] Cache Server Hostname 
[Reserved forfuture use] Cache Server Hostname 
Comment: 
C) Not Configured 
Previous Setting 
Next Setting 
@ Enabled 
C) Disabled 
Options: 
Cache Server: 
sccm01-2019.adg.local 
Supported on: 
At least Windows Server 2016, Windows 10 
Help: 
[Reserved for future use]l
Group Policy from Windows 10 1909 Group Policy Templates

“[Reserved for future use] Cache Server Hostname”: [Reserved for future use]

In the Insider version of 20H1 (Build 19041) the “[Reseved for future use]” has disappeared from the name and description. The following is written in the policy:

This policy allows you to set one or more Delivery Optimization in Network Cache servers that will be used by your client(s).

One or more values can be added as either fully qualified domain names (FQDN) or IP addresses. To add multiple values, separate each FQDN or IP address by commas.

Group Policy from Windows 10 1909 Group Policy Templates
"Group ID": Group ID must be set as a GUID. This Policy specifies an arbitrary group ID that the device belongs to.
Use this if you need to create a single group for Local Network Peering for branches that are on different domains or are not on the same LAN.
Note: this is a best effort optimization and should not be relied on for an authentication of identity.
Group Policy from Windows 10 1909 Group Policy Templates

“Group ID”: Group ID must be set as a GUID. This Policy specifies an arbitrary group ID that the device belongs to.
Use this if you need to create a single group for Local Network Peering for branches that are on different domains or are not on the same LAN.
Note: this is a best effort optimization and should not be relied on for an authentication of identity.

In the Insider version of 20H1 (Build 19041) the description is the same.

Group Policy from Windows 10 1909 Group Policy Templates

"Select the Source of Group IDs": Set this policy to restrict peer selection to a specific source. 
Options available are: 
1 = AD Site.
2 = Authenticated domain SID.
3 = DHCP Option ID.
4 = DNS Suffix. 
5 = AAD Tenant ID. 
When set, the Group ID will be assigned automatically from the selected source. If you set this policy, the GroupID policy will be ignored. 
The options set in this policy only apply to Group (2) download mode. If Group (2) isn't set as Download mode, this policy will be ignored. 
For option 3 - DHCP Option ID, the client will query DHCP Option ID 234 and use the returned GUID value as the Group ID.
Group Policy from Windows 10 1909 Group Policy Templates

“Select the Source of Group IDs”: Set this policy to restrict peer selection to a specific source.
Options available are:
1 = AD Site.
2 = Authenticated domain SID.
3 = DHCP Option ID.
4 = DNS Suffix.
5 = AAD Tenant ID.
When set, the Group ID will be assigned automatically from the selected source. If you set this policy, the GroupID policy will be ignored.
The options set in this policy only apply to Group (2) download mode. If Group (2) isn’t set as Download mode, this policy will be ignored.
For option 3 – DHCP Option ID, the client will query DHCP Option ID 234 and use the returned GUID value as the Group ID.

In the Insider version of 2004 (Build 19041) the description is the same.

Group Policy from Windows 10 20H1 Release Preview: Cache Server Hostname Source DHCP Option 235
Group Policy from Windows 10 20H1 Release Preview: Cache Server Hostname Source DHCP Option 235

Added in the Insider version 2004 (Build 19041) is the option to overwrite the hostname from the above policy with a DHCP option.

Configuring Connected Cache via Intune

For Intune systems, the configuration can be done via a “Delivery Optimization” configuration.

Delivery Optimization Policy in Microsoft Intune
Delivery Optimization Policy in Microsoft Intune

The hostname cannot be set. I assume that this option will be retrofitted. Alternatively, Oliver Kieselbach has searched for the OMA-URI in his blog post.

DHCP Optionen for Connected Cache

As I just read, there are a few DHCP custom options that can be set. These are:

Option 234: Connected Cache / DO Group ID as GUID

Option 235: Cache Server

These options will probably be supported by Windows 10 2004, but it is not possible to say exactly because it is still a preview at the moment.

Personal conclusion

I think this is a step in the right direction. I try to experiment a little bit more with the different Windows versions in the lab, what works really well from which version on. Now Connected Cache only needs to be available as a stand-alone server application. And no, I didn’t try if the Power Shell installer which is located in the SCCM directory “SMS_DP$” works without SCCM.

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Author: Fabian Niesen

Fabian Niesen has been working as an IT consultant for years. Here he writes privately and independently of his employer. Among others he is certified as MCSA Windows Server 2008 / 2012, MCSA Office 365, MCSA Windows 10, MCSE Messaging, MCT and Novell Certified Linux Administrator. Since 2016 he is also MCT Regional Lead for Germany. His hobbies are social media, blogging, medieval markets, historical songs and house building.

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