CMMC Practice Requirement:

Prevent remote devices from simultaneously establishing non-remote connections with organizational systems and communicating via some other connection to resources in external networks (i.e., split tunneling).

CMMC Requirement Explanation:

A virtual private network (VPN) is a virtual network built on top of existing networks that can provide a secure communications mechanism between networks. A common example is a VPN tunnel that connects an employee’s laptop to the company’s network. The split tunneling feature in a VPN allows a mobile user to access a public network (e.g., the internet) and a virtual private network (VPN) (e.g.,, your organization’s network) at the same time, as a result, the user’s traffic is not going through one encrypted tunnel controlled by your organization. The split tunneling feature on your VPN should be disabled, this can often be accomplished by accessing the settings in your VPN appliance.

Example CMMC Implementation:

If your company uses a virtual private network (VPN) you need to disable the “split tunneling” feature in your VPN.

Scenario(s):

- Scenario 1:

Example:

John is a remote employee that works from home and uses his company’s VPN to access the corporate file server located on his company’s network. Luckily for John, the IT team at his company has not yet disabled split tunneling in the VPN, so he can still access the printer on his home network while accessing files on his company’s network via the VPN. To meet CMMC requirements, the IT team disables split tunneling. As a result, John can no longer access the printer located on his home network while he is connected to his company’s VPN. John can still access the corporate file server while connected to the VPN.
A network diagram depicting split tunneling via a VPN connection
A network diagram depicting split tunneling via a VPN connection
 

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