Sticky IP prioritization based on IP pool and subnet by DHCP

1. A method for handling Dynamic Host Configuration Protocol (DHCP) at a first DHCP server, said method comprising steps of:

assigning a priority to each of a plurality of subnets;

receiving a DHCP Discover message from a client;

in response to receipt of a DHCP Discover message from a client, determining if said client had a previously assigned IP address;

determining if said previously assigned IP address is still available;

responsive to said previously assigned IP address being available determining if said previously assigned IP address is in a subnet having a highest priority;

responsive to said previously assigned IP address being in a subnet having a highest priority, selecting said previously assigned IP address; and

transmitting a DHCP Offer message to said client, offering said selected IP address.

2. The method of claim 1 , wherein said assigning a priority comprises receiving input from an operator.

3. The method of claim 1 , wherein said assigning a priority comprises receiving input from a configuration file.

4. The method of claim 1 , wherein if said previously assigned IP address is not in a subnet having a highest priority, selecting an Internet Protocol (IP) address from a subnet having a highest priority.

5. The method of claim 1 , further comprising steps of identifying at said first DHCP server, fully used subnets; partially used subnets; and unused subnets;

first migrating unused subnets from said first DHCP server to a second DHCP server;

migrating fully used subnets from said first DHCP server to said second DHCP server; and

then migrating partially used subnets from said first DHCP server to said second DHCP server.

6. A DHCP server, comprising:

a processor; and

a memory communicatively connected to the processor, the memory having stored thereon instructions which, when executed by the processor, cause the processor to:

assign a priority to each of a plurality of subnets;

receive a DHCP Discover message from a client;

in response to receipt of a DHCP Discover message from a client, determine if said client had a previously assigned IP address;

determine if said previously assigned IP address is still available;

responsive to said previously assigned IP address being available, determine if said previously assigned IP address is in a subnet having a highest priority;

responsive to said previously assigned IP address being in a subnet having a highest priority, select said previously assigned IP address; and

transmit a DHCP Offer message to said client, offering said selected IP address.

7. A program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine to perform the steps of:

assigning a priority to each of a plurality of subnets;

receiving a DHCP Discover message from a client;

in response to receipt of a DHCP Discover message from a client, determining if said client had a previously assigned IP address;

determining if said previously assigned IP address is still available;

responsive to said previously assigned IP address being available determining if said previously assigned IP address is in a subnet having a highest priority;

responsive to said previously assigned IP address being in a subnet having a highest priority, selecting said previously assigned IP address; and

transmitting a DHCP Offer message to said client, offering said selected IP address.

8. The DHCP server of claim 6 , wherein said assigning a priority comprises receiving input from an operator.

9. The DHCP server of claim 6 , wherein said assigning a priority comprises receiving input from a configuration file.

10. The DHCP server of claim 6 , wherein if said previously assigned IP address is not in a subnet having a highest priority, the instructions cause the processor to select an Internet Protocol (IP) address from a subnet having a highest priority.

11. The DHCP server of claim 6 , wherein the instructions further cause the processor to: identify at said first DHCP server, fully used subnets; partially used subnets; and unused subnets;

first migrate unused subnets from said first DHCP server to a second DHCP server;

migrate fully used subnets from said first DHCP server to said second DHCP server; and

then migrate partially used subnets from said first DHCP server to said second DHCP server.

12. The program storage device of claim 7 , wherein said assigning a priority comprises receiving input from an operator.

13. The program storage device of claim 7 , wherein said assigning a priority comprises receiving input from a configuration file.

14. The program storage device of claim 7 , wherein if said previously assigned IP address is not in a subnet having a highest priority, selecting an Internet Protocol (IP) address from a subnet having a highest priority.

15. The program storage device of claim 7 , further comprising steps of identifying at said first DHCP server, fully used subnets; partially used subnets; and unused subnets;

first migrating unused subnets from said first DHCP server to a second DHCP server;

migrating fully used subnets from said first DHCP server to said second DHCP server; and

then migrating partially used subnets from said first DHCP server to said second DHCP server.