For the OpenVPN Access Server product we have the subscription licensing model which requires constant direct access (so not through a proxy) to the server asb.sts.openvpn.net on port TCP 443. If the interruption gets interrupted for a short while, like a few minutes or a few hours, that is not a problem, as the system is robust enough to function and accept new VPN connections even during such events (so long as you were not already at your limit yet). This software licensing model is flexible and allows multiple activations and sharing of a license across multiple Access Servers and lets you change the amount of connections allowed.
We also have the fixed license model which requires one-time direct access (so not through a proxy) for activation and renewals to licensing.openvpn.net at port TCP 443 in order to complete activation. This model does come with some drawbacks as it is single-activation only, cannot be shared across multiple Access Server nodes, and is of a fixed size which cannot be altered later on, although you can add additional fixed licenses on the same Access Server to increase its amount of allowed connections. They simply add up.
On Amazon AWS on the AWS Marketplace we also offered the tiered instances which are automatically licensed by reading specific metadata from the EC2 instance when launching our OpenVPN Access Server from the AWS Marketplace directly. These tiered instances can be recognized by the (xx connected devices) in the title of the offering on the AWS Marketplace. These are licensed for the stated amount of connections automatically through the Amazon AWS services and requires access to awspc1.openvpn.net at port TCP 443. There are also 3 backup licensing servers it can use (awspc2.openvpn.net, awspc3.openvpn.net, awspc4.openvpn.net) to get licensed and billed automatically through Amazon AWS.
If however your system is installed somewhere where Internet access is not possible or not allowed, then it is possible to do an installation of Access Server by downloading the Access Server package manually and installing it yourself, and then doing an offline activation. This uses the fixed license model. This can be done by us when you contact us and request an offline activation and provide us with the necessary hardware activation file, or you can do it yourself using a second Access Server installation that does have access to the Internet, and which can be provided with the necessary hardware activation file, after which the resulting activated key file can be manually transferred and stored on the file system of the Access Server.
For more information about the pricing for OpenVPN Access Server software licenses see the Access Server pricing page.
For more information and technical details about connection requirements see the troubleshooting software licensing page.