Hello Richard-UK,
The article below will provide you with VPN settings overview for Apple devices.
You can configure VPN settings for an iPhone, iPad, or Mac enrolled in a mobile device management (MDM) solution. Use the VPN payload to enter the VPN settings for connecting to your network. Settings you specify in the configuration profile can’t be modified by users. Some VPN and Wi-Fi settings, such as 802.1X parameters, can be set only by a configuration profile.
Note: An identity is required for some VPN configurations. Depending on the VPN configuration, a VPN payload may require that the associated Certificates payload contain the certificate associated with the identity.
The VPN payload supports the following. For more information, see Payload information. To see a list of VPN variables, see Variables settings for MDM payloads for Apple devices.
* Supported payload identifier: com.apple.vpn.managed
* Supported operating systems and channels: iOS, iPadOS, macOS device, macOS user.
* Supported enrollment types: User Enrollment (App-Layer VPN and App-to-App Layer VPN mapping only), Device Enrollment, Automated Device Enrollment.
* Duplicates allowed: True—more than one VPN payload can be delivered to a user or device.
You can use the settings in the table below with the VPN payload.
VPN settings overview for Apple devices - Apple Support
Another great article about VPN security is: Virtual private network (VPN) security - Apple Support
If you're using any third-party security software this article will come on handy: Check VPN (Virtual Private Network) and third-party software to help resolve network connectivity issues - Apple
Support
Let us know if you have any questions.
Thank you for using Apple Support Communities.
Take care!