On July 18th from 0400 – 0800 UTC, we will be performing general maintenance on our datacenter infrastructure in all regions. During this time, lab users may experience short, transient connectivity issues while infrastructure fails over to secondary resources. No data for running instances should be affected.

We will also be performing maintenance on our core infrastructure for Lab on Demand. During this time, connectivity to lab instances may be impacted, and new launches may fail. This should also have no effect on current running instances data.


Our current quarterly maintenance schedule can be found here: https://www.learnondemandsystems.com/maintenance-schedule/

Hyper-V Hosted Lab


To launch and use a Hyper-V hosted lab, the following requirements must be met:
  1. Have a supported browser. (IE 8+, Edge 1+, Chrome 16+, Firefox 11+, Safari 6+)
  2. Be connected to a network that allows at least one of the following:
    1. Secure Web sockets on port 443 (HTML5 control)
    2. Web sockets over HTTP port 80 and HTTP over Port 843 (Flash control)
    3. HTTPS over port 443 (Silverlight control)
    4. RDP over port 21xxx or 443 (Enhanced control)
  3. If you are installing the Enhanced control, you must have administrative rights on the local machine.

Browser/Control Support

Machines in your lab can be accessed using any one of four virtual machine controls. You can freely change between controls to find the one that works best for you.

Control Internet Explorer Microsoft Edge Firefox Chrome Safari
Version Protocol Ports Version Protocol Ports Version Protocol Ports Version Protocol Ports Version Protocol Ports
HTML51 10+ Websockets 443 1+ Websockets 443 11+ Websockets 443 16+ Websockets 443 6+ Websockets 443
Flash Flash 11+ Websockets 80 & 8432 Flash 11+ Websockets 80 & 8432 Flash 11+ Websockets 80 & 8432 Flash 11+ Websockets 80 & 8432 Flash 11+ Websockets 80 & 8432
Silverlight Silverlight 4+ HTTP 443 NA NA NA Silverlight 4+ HTTPS 443 Silverlight 4+ HTTP 443 Silverlight 4+ HTTP 80
Enhanced3,4 8+ RDP 21xxx or 443 NA NA NA NA NA NA NA NA NA NA NA NA
1 Preferred client
2 Port 843 is required by Flash Socket Policy to authorize the use of Websockets
3 Requires Internet Explorer. The 21xxx value depends on which host server in the cloud the lab is running on. If connection on port 21xxx fails, the Enhanced client will rollover and attempt the connection on port 443.
4 Internet connections that traverse a proxy are not supported.

Important Note: When Using Windows Server Operating Systems

When connecting to Learn on Demand Systems Training Management Systems (TMS) portals with a computer having Windows Server operating systems on it, you may experience difficulty in connecting to the sign-in page or clicking on some buttons. Steps to remediate can be found here.

Connection Assessment Test

If you are experiencing frequent disconnects or lag when controlling your machines, you may be asked to run a connection assessment test.

Firewall Exception Rule Information

For those that need to create a firewall exception rule to allow connectivity to the Lab on Demand servers (this isn't common), the following information can be used to create a limited destination rule to only allow the above protocols and ports from your network to the Lab on Demand cloud.
  • Domain Names: *.labondemand.com, *.learnondemandsystems.com, *.learnondemand.net, *.holsystems.com
  • IP Range:, -, -,

The Lab on Demand system is a cloud platform that automatically provisions and connects the learner with private sandboxed resources. There is no way to predict which IP address in the cloud the learner will connect to for the provisioning of their virtual machines. This is why we provide a range of IP addresses and only a second level domain name.

The domains and IP addresses in the table below may also be required as firewall exceptions. We strongly encourage using names, and not IP addresses, for firewall and proxy configuration if at all possible, as the IP addresses may change without warning (and without documentation update). This allows access even in network failover and future geographic targeting scenarios. If specific IP addresses must be used, use the following table as a guide for IP addresses:

DNS name IP Address 1 IP Address 2
holsystems.blob.windowsazure.com (refer to Microsoft's documentation)
holsystems.blob.core.windows.net (refer to Microsoft's documentation)

Lab Software Whitelisting Information

Software that communicates with remote servers outside of the lab environment may need addresses whitelisted with the vendor to work. The below address ranges are used by NAT internet access labs.

  • IP Ranges: -, –,,,