DHCP client tool

I want to allocate myself four IP addresses from a DHCP pool. I am looking for a tool or script that runs on Linux, makes DHCP requests that look as if they came from four different devices, and reports what IP addresses were allocated. After this, I run the tool every <n> hours to renew the lease.

I realize that the correct way to do this is to talk to the admin, ask them to give me four addresses and then remove these addresses from the DHCP pool. This is going to be hard if not impossible.

Also I don't have real devices that can make DHCP requests. These four addresses will be assigned to any of several VMs on a need basis ("floating IPs" in OpenStack parlance).

Any tool recommendations?