Virtual private network connection status detection

A system of a virtual private network (VPN) service provider infrastructure (SPI), the system comprising:

• one or more non-transitory memories storing instructions;
• and
• one or more processors that execute the instructions to:
• allocate, by the apparatus, resources of the VPN SPI to a client device to enable the client device to communicate via a VPN associated with the VPN SPI in response to receiving a VPN connection request from the client device;
• monitor VPN activity of the client device by receiving one or more handshake notifications from the client device, wherein receiving a handshake notification of the one or more handshake notifications comprises:
• receiving requests, from the client device after the client device was granted access to the VPN, to download or upload data via the VPN, wherein at least a portion of the requests are received according to a schedule, wherein the schedule corresponds to a VPN-connected phase, wherein, upon the client device losing connection to the VPN, the schedule switches to a connection lost phase specifying that a time difference between transmission, by the client device, of at least one pair of successive packets is an exponential function of a number of packets sent since the connection was lost, and
• storing timestamps associated with the requests to download or upload the data;
• in response to monitoring the VPN activity of the client device, determine that the client device has not communicated via the VPN for at least a threshold time period based on a calculated time difference between a current time and a stored timestamp of a latest-in-time handshake notification from the client device, wherein the threshold time period is determined based on a corresponding phase of the schedule;
• and
• add the resources allocated to the client device to a resource pool for provision to devices connecting to the VPN.

One or more non-transitory computer readable media storing instructions that, when executed by one or more machines of a virtual private network (VPN) service provider infrastructure (SPI), cause the one or more machines to perform operations comprising:

• allocating, by the one or more machines of the VPN SPI, resources of the VPN SPI to a client device to enable the client device to communicate via a VPN associated with the VPN SPI in response to receiving a VPN connection request from the client device;
• monitoring VPN activity of the client device by receiving handshake notifications from the client device, wherein receiving the handshake notifications comprises:
• receiving requests, from the client device after the client device was granted access to the VPN, to download or upload data via the VPN, wherein at least a portion of the requests are received according to a schedule, wherein the schedule corresponds to a VPN-connected phase, wherein, upon the client device losing connection to the VPN, the schedule switches to a connection lost phase specifying that a time difference between transmission, by the client device, of at least one pair of successive packets is an exponential function of a number of packets sent since the connection was lost, and
• storing timestamps associated with the requests to download or upload the data;
• in response to monitoring the VPN activity of the client device, determining that the client device has not communicated via the VPN for at least a threshold time period based on a calculated time difference between a current time and a stored timestamp of a latest-in-time handshake notification from the client device, wherein the threshold time period is determined based on a corresponding phase of the schedule;
• and
• adding the resources allocated to the client device to a resource pool for provision to devices connecting to the VPN.