How to really install Office LTSC 2024 offline from local source and stop ODT to try to access Internet?

Question

Hello,

This is a new question as requested in my reply in post https://learn.microsoft.com/en-gb/answers/questions/5670183/installation-of-ltsc-2024-in-virtual-machine-witho

I try to install Office LTSC 2024 in an environment without Internet Access using ODT. Downloading and installing from a local folder, as explained in the referenced post, works.

However, the big issue is that it takes ages. Installation is really slow. Looking at the log files shows many attempts to connect to the Internet even though it shouldn't. This causes many timeouts and increase installation time for nothing. The measured difference is huge, from 15 minutes without Internet connection to only 5 minutes with Internet connection (both with the same configuration file and local folder of course).

To go further, even if I try to run setup.exe /? to get help, it takes 4 minutes... and returns nothing. Log files show many time gaps between actions, reflecting the timeout. There are many entries named "Activity" or "Telemetry".

Here is an example, among many (look at Duration, which is huge):

 [Moderator note: Personally Identifiable Information removed]

How can we totally disable CDN connections? How to really use ODT in an offline environment? Having a local source should not trigger any Internet connections, it defeats the purpose.

This is really an issue when you have to install Office on many machines and when you prepare/image your computers.

Many thanks for your help.

Answer 1

Hello Ivory,

Many thanks for your detailed answer, explaining how ODT behaves underhood.

A few days ago, I tried to use the hosts file but it was still slow. I tried again this morning and I figured out that all endpoints have to be set in the hosts file. If one is missing, it will be slow (which is logical as the request will go through DNS and then timeout).

Looking at my DNS server logs, I found other endpoints that try to be reached by ODT. Adding them to my hosts file finally make it work and enables me to install Office LTSC 2024 offline in 5 minutes instead of 15.

So the complete list of endpoints to add to the C:\Windows\System32\drivers\etc\hosts file is:

[Moderator note: Personally Identifiable Information removed] ecs.office.com

[Moderator note: Personally Identifiable Information removed] config.office.com

[Moderator note: Personally Identifiable Information removed] officecdn.microsoft.com

[Moderator note: Personally Identifiable Information removed] officeclient.microsoft.com

[Moderator note: Personally Identifiable Information removed] nexus.officeapps.live.com

[Moderator note: Personally Identifiable Information removed] self.events.data.microsoft.com

[Moderator note: Personally Identifiable Information removed] clients.config.office.net

[Moderator note: Personally Identifiable Information removed] nexusrules.officeapps.live.com

[Moderator note: Personally Identifiable Information removed] login.live.com

[Moderator note: Personally Identifiable Information removed] mobile.events.data.microsoft.com

[Moderator note: Personally Identifiable Information removed] ctldl.windowsupdate.com

[Moderator note: Personally Identifiable Information removed] login.microsoftonline.com

[Moderator note: Personally Identifiable Information removed] optimizationguide-pa.googleapis.com

I hope it can help.

Thanks.

Answer 2

Hi FBACHPG98-6666,

The delay isn't Office actually trying to install over the internet, it's the setup process making normal background calls (to Microsoft's Experimentation and Configuration Service and related endpoints) that would normally return in milliseconds. In your environment, the network adapter is reachable but has no route to the internet, so each of these calls has to sit and wait for a full connection timeout before giving up. That's the multi-second (sometimes 80+ second) gaps you're seeing in the log for entries like "Office.Experimentation.EcsFetch."

There's no supported Office Deployment Tool setting that fully disables these calls. It isn't something you can switch off in configuration.xml.

Hosts file null-route point the relevant endpoints at your address. DNS resolves immediately, and since nothing's listening on your address, the connection is refused in milliseconds instead of hanging for 80+ seconds. Add entries for:

ecs.office.com

config.office.com

officecdn.microsoft.com

officeclient.microsoft.com

nexus.officeapps.live.com

self.events.data.microsoft.com

clients.config.office.net

This makes DNS resolve straight away and the connection get refused instantly (nothing's listening on localhost), instead of hanging for the full timeout period on each call.

If these machines are being built from a golden image, the cleanest option is to install Office as part of image preparation while that reference machine still has internet access  then capture/generalize the image afterwards. Deployed machines then never need to run setup.exe at all, so this delay never shows up on the fleet; it only happens once, on the machine used to build the image.

However, I believe the best next step for your IT admin is creating a support ticket through the Microsoft 365 Admin Center > Support > Help & Support to have Microsoft Support agent assist you in this regard

Turn off the "Support Assistant" feature.  

Use the keyword "Support" to quickly bypass automated suggestions > Select Contact Support.  

 

In the ticket description, please clearly describe the issue, including any error messages or codes and the steps you’ve already tried. You can also attach screenshots or screen recordings. Additionally, sharing your preferred contact times may help the support team handle the case more efficiently.   

A technical support engineer can perform a remote session to investigate the situation, verify the backend configurations, and run any necessary synchronization tools to resolve the problem. If the issue requires further attention, they can escalate it to a specialized team for deeper analysis.    

If you have any questions or need further support, please don’t hesitate to reach out at any time. 

Thank you for your patience and understanding. 

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