A method is provided of dynamically allocating an IP address, via a DHCP relay, to a client terminal within a communication network. The DHCP relay is able to choose the IP address within at least one first set of IP addresses that is administered by an entity for managing sets of IP addresses. The method implements: a first step of transmitting, to the entity for managing sets of IP addresses, a request to allocate an IP address to the client terminal; a second step in which the entity for managing sets of IP addresses selects a set of IP addresses within which to choose the IP address to be allocated from among: either the at least one first set of IP addresses; or at least one second set of IP addresses that is newly created as a function of at least one predetermined parameter; and a third step of allocating in respect of the client terminal at least one IP address chosen by the DHCP relay in the selected set of IP addresses.