1. A computer-implemented method comprising: receiving a request to allocate an Internet Protocol (IP) address, the request comprising data that identifies an entity requesting allocation of the IP address; determining, by one or more processing units, that a target block of a plurality of blocks of contiguous IP addresses comprises at least as many unallocated contiguous IP addresses as any other block of the plurality of blocks; splitting, by the one or more processing units, the target block into a first block and a second block of unequal size based at least on the determination that the target block comprises at least as many unallocated contiguous IP addresses as any other block of the plurality of blocks, the IP addresses of the second block each higher than any IP address of the first block, respective sizes of the first block and the second block being determined based at least in part on one or more parameters; and assigning the second block to the entity and allocating a lowest IP address of the second block to the entity.