Virtual private network resource management

1. A method comprising:

receiving, by a machine associated with a virtual private network (VPN) service provider infrastructure (SPI), a VPN connection request from a client device;

assigning, by the machine, a resource to the client device for use in accessing a VPN of the VPN SPI;

receiving, by the machine, echo request packets from the client device, the echo request packets being received according to a schedule selected based on a connection status between the client device and the VPN; and

in response to determining that a threshold time period has passed since a latest-in-time echo request packet of the echo request packets:

initiating transmission, from the machine to the client device, of a message indicating that the client device is being disconnected from the VPN;

preventing, by the machine, further use of the assigned resource by the client device; and

adding, by the machine, the assigned resource of the client device to a pool of available resources, wherein the threshold time period is determined based on the schedule, wherein the schedule specifies that an echo request packet is to be received 2 n seconds since an immediately prior echo request packet was received, wherein n is a total count of echo request packets transmitted since a connection between the client device and the VPN was lost, while n is less than a first threshold number p, where p is a positive number greater than 1, and the echo request packet is to be received at a preset number of seconds that is greater than 2 p-1 seconds when n is equal to or greater than p.

2. The method of claim 1 , wherein the machine associated with the VPN SPI comprises a VPN server.

3. The method of claim 1 , further comprising:

transmitting, to the client device, the message indicating that the client device is being disconnected from the VPN.

4. The method of claim 1 , wherein the resource comprises an Internet Protocol (IP) address for accessing the VPN.

5. The method of claim 1 , further comprising:

transmitting an echo reply packet in response to at least one of the echo request packets.

6. The method of claim 1 , wherein determining that the threshold time period has passed since the latest-in-time echo request packet comprises:

computing a time difference between a current time and a time associated with the latest-in-time echo request packet; and

determining that the time difference is greater than or equal to the threshold time period.

7. The method of claim 1 , wherein the pool of available resources stores multiple unallocated resources.

8. An apparatus comprising:

a non-transitory memory storing instructions; and

a processor that executes the instructions to:

receive, by a machine associated with a virtual private network (VPN) service provider infrastructure (SPI), a VPN connection request from a client device;

assign, by the machine, a resource to the client device for use in accessing a VPN of the VPN SPI;

receive, by the machine, echo request packets from the client device, the echo request packets being received according to a schedule selected based on a connection status between the client device and the VPN; and

in response to determining that a threshold time period has passed since a latest-in-time echo request packet of the echo request packets:

initiate transmission, from the machine to the client device, of a message indicating that the client device is being disconnected from the VPN;

prevent, by the machine, further use of the assigned resource by the client device; and

add, by the machine, the assigned resource of the client device to a pool of available resources, wherein the threshold time period is determined based on the schedule, wherein the schedule specifies that an echo request packet is to be received 2 n seconds since an immediately prior echo request packet was received, wherein n is a total count of echo request packets transmitted since a connection between the client device and the VPN was lost, while n is less than a first threshold number p, where p is a positive number greater than 1, and the echo request packet is to be received at a preset number of seconds that is greater than 2 p-1 seconds when n is equal to or greater than p.

9. The apparatus of claim 8 , wherein the machine associated with the VPN SPI comprises a VPN server.

10. The apparatus of claim 8 , wherein the processor further executes the instructions to:

transmit, to the client device, the message indicating that the client device is being disconnected from the VPN.

11. The apparatus of claim 8 , wherein the resource comprises an Internet Protocol (IP) address for accessing the VPN.

12. The apparatus of claim 8 , wherein the processor further executes the instructions to:

transmit an echo reply packet in response to at least one of the echo request packets.

13. The apparatus of claim 8 , wherein determining that the threshold time period has passed since the latest-in-time echo request packet comprises:

computing a time difference between a current time and a time associated with the latest-in-time echo request packet; and

determining that the time difference is greater than or equal to the threshold time period.

14. The apparatus of claim 8 , wherein the pool of available resources stores multiple unallocated resources.

15. A non-transitory computer readable medium storing instructions that, when executed by a computer, cause the computer to perform operations comprising:

receiving, by a machine associated with a virtual private network (VPN) service provider infrastructure (SPI), a VPN connection request from a client device;

assigning a resource to the client device for use in accessing a VPN of the VPN SPI,

receiving, by the machine, echo request packets from the client device, the echo request packets being received according to a schedule selected based on a connection status between the client device and the VPN; and

in response to determining that a threshold time period has passed since a latest-in-time echo request packet of the echo request packets:

initiating transmission, from the machine to the client device, of a message indicating that the client device is being disconnected from the VPN,

preventing, by the machine, further use of the assigned resource by the client device; and

adding, by the machine, the assigned resource of the client device to a pool of available resources, wherein the threshold time period is determined based on the schedule, wherein the schedule specifies that an echo request packet is to be received 2 n seconds since an immediately prior echo request packet was received, wherein n is a total count of echo request packets transmitted since a connection between the client device and the VPN was lost, while n is less than a first threshold number p, where p is a positive number greater than 1, and the echo request packet is to be received at a preset number of seconds that is greater than 2 p-1 seconds when n is equal to or greater than p.

16. The computer readable medium of claim 15 , wherein the machine associated with the VPN SPI comprises a VPN server.

17. The computer readable medium of claim 15 , the operations further comprising:

transmitting, to the client device, the message indicating that the client device is being disconnected from the VPN.

18. The computer readable medium of claim 15 , the operations wherein the resource comprises an Internet Protocol (IP) address for accessing the VPN.

19. The computer readable medium of claim 15 , the operations further comprising:

transmitting an echo reply packet in response to at least one of the echo request packets.

20. The computer readable medium of claim 15 , wherein determining that the threshold time period has passed since the latest-in-time echo request packet comprises:

computing a time difference between a current time and a time associated with the latest-in-time echo request packet; and

determining that the time difference is greater than or equal to the threshold time period.