MAC addresses are flexibly and dynamically allocated across groups of devices that need MAC addresses. MAC address pools are defined for the groups by non-overlapping ranges of MAC addresses. The range of MAC addresses defined for any pool may be shrunk to support an expansion of the range of MAC addresses of another pool. The maximum number of universally-administered MAC addresses that can be defined for any MAC address pool is greater than 216, and the maximum number of locally-administered MAC addresses that can be defined for any MAC address pool is greater than 238.